I also have an overheating problem. I think I have a Cat motor. I have only had this coach about 2 years, and when I purchased it the previous owner had just had a brand new radiator installed, apparently he was also having temp problems and failed to mention it to me.
My problem is it heats up on the slightest uphill grade. We are in AZ, and I have only made one short 400 mile trip with it. Can some of you guys please tell this dumb OLD (84yrs) Cowboy where to start looking for the problem??
Any and all help/suggestions truly appreciated.
Rick
We need to know which Cat engine,miles on engine the more info the better we can help,which oil,etc,when filters were changed.
Do you have a infared gun to verify the temps?
Boil a thin metal container of water. Turn off the heat and aim your infrared pyrometer at the side. If it read 212F you're in the USA, 100C you're in Canada.
Art
A leaking head gasket can cause overheating. Easy to check for products of combustion with the radiator cap off. Read here: 8 Essential Cooling System Checks and How to Perform Them (https://www.onallcylinders.com/2014/06/25/8-must-cooling-system-checks/)
Check the air cleaner. Restricted air cleaner may cause the engine to be overfueled with increased heat.
Marginal cooling will be worse at high altitudes.
Drop a gear and keep RPM up on grades.
Pierce
Rick, how about downshifting and going slower up hills. This was our answer to heat gain.
Wowwwww, thanks for all the great suggestions. Here is what I know and what I don't know at this point.
HERE IS WHAT I KNOW
The motor is a 3208-T Cat as Mike & Pamela mentioned.
The motor has 182,671 miles on it.
The radiator is in the rear of the coach.
There are two (2) small air scoopes on each side to bring air into the motor compartment but do not know if they are factory installed or add on's.
We took it in to the Napa dealer and had all the filters and fluids changed right when we purchased it.
The radiator was brand new when I purchased the coach.
WHAT I DON'T KNOW
Have not checked to see what the thermostat looks like, and do not know if a new one was installed when the radiator was replaced.
Do not know the temp of the engine, but will by Friday as I have ordered an infared gun and a antifreeze/water coolent hydrometer.
Have not checked the fan belt, the rotation and speed of the fan blade, nor have I checked to see if it is pulling or pushing the air as I read about in another post.
MIKE
What pictures should I take and post?
Thanks again guys for all helpful advice. I was also wondering, should I start a NEW post as have kinda hijacked this one and don't wan to step on any toes !
Rick
Rick,
I was just wanting you to post a pic. of the engine if you weren't sure what engine you have. That way we could see, as a pic. is worth like a lot of words. With you knowing it is a 3208 then there is no need to post a pic of the engine.
Mike
Oh, got it Mike... Thanks
I have split this topic off, as it is not related to overheating of a Cummins 8.3 with side radiator.
I was worried that might be the case, thanks for the split Brett, I really appreciate it.
Rick
When I worked for Foretravel in Florida we were having overheating issues with the 240 with the 3116 engines. We had to add much belting material around the radiator to make sure that the air didn't bypass the radiator and that seemed to help.
Make sure your rear radiator isn't plugged up. Oil and other liquids (rain off the road, etc.) get pushed into the fins and act like a dirt magnet. My 1981 Foretravel had a 3208 and a rear radiator that was filthy when I bought it. I had problem with heat.
Simple green and a couple hours at the car wash solved the problem and I made a habit of repeating that process on a regular basis.
If you flatten a plastic straw and insert it between your radiator fins you may be surprised at how much crap is in there. Keep washing until it is clean.
I also do this on my 1993 U225's rear radiator.
As for climbing grades, get in the right lane, downshift, put on your flashers and watch your temp gauge.
To be clear, on a rear radiator, it MUST be cleaned from the front.
The front of the CAC is where most of the dirt and debris will be deposited.
The 2 belts that drive the fan can be a little loose and slip enough to result in this symptom.
The T stat is probably ok as it runs fine until high loading .
If there is black smoke at high power , maybe the fuel pump is turned up for more power and resulting heat . The pump has a safety wire on it from the factory. Maybe it has been turned up.
If the oe muffler is still there, that will add to the heat.
I found that the coolant can be low and the temp can creep up. Top it up , it will overflow until it's at a happy level .
Mine had no recovery bottle but I added one.
The cap should be a 9 or 13 # . Mine is 9 .
You may also remove the rear door and see how much it helps. It drops my temp by 10 f
Also. , verify that the oe shroud is intact . It allows the fan to do its job. Slim chance that it was left out when the new rad was te installed.
Boy what a bunch of all great ideas and suggestions. I will take every one of them into account tomorrow when I get back home in the afternoon. Don't mind working outside now that the temperature is going to be back down in the lower 100's. Was 114 outside on the back porch today, in the shade of course!!
Thanks to each and everyone of you.
Rick
Have had pros and cons thruout the years but if everything above is in working order I would change to synthetic oil and see if
that helps,the Amsoil 10w40 does run cooler then dino oil,I have never seen 210 degrees,on some downhills I have seen 180 and below,most of the time we run at 180 degrees,also have it in the hyd system.
Would it be ok to plug in a separate temp gage to double check the one in the dash? Does anyone know where the temperature sender is on my Cat 3208 motor, and the FT part number?
Rick
While I agree that having an accurate temperature gauge would be a good idea.
But, since your gauge shows a temperature rise "on the slightest grade", you KNOW you have an engine temperature issue/inadequate cooling even though you may not know the exact temperature.
BTW, my suggested absolute first step is to replace the thermostat(s) (Cat calls them regulators) and gasket(s). You could even consider this routing preventive maintenance.
Same for cleaning the front of your CAC, again ASSUMING you have a rear radiator.
Mine does not have a CAC
The 300 should , but with side radiator?
Maybe the build date is late 88.
So, normally aspirated 3208??
Again we are having to do a lot of guessing here.
Please confirm:
Rear radiator?
Normally aspirated?
Turbo with no after-cooler?
Turbo with after-cooler= CAC?
Yes 1992 was a huge transition year for Foretravel mechanicals as the new in-line engines replace the older generation V8's.
According to reply $5, it's a 3208T so turbo charged. It could either have an intercooler in front of the radiator or none at all.
Some CATs had air to liquid intercoolers but this is more costly so probably air to air.
Our Detroit has an air to liquid aftercooler mounted below the turbo and blower so you can't see it as it sits down in the valley of the V6 diesel.
Air to liquid intercoolers are smaller in size but more expensive. You can mount them most anywhere.
Both intercoolers and aftercoolers may be referred to as CAC in the RV community.
Here is a good site: Air To Water Intercooler Tech 101: What It Does And What You Need | Technolog... (https://burnsstainless.com/blogs/articles-1/air-to-water-intercooler-tech-101-what-it-does-and-what-you-need)
Pierce
250 hp is turbo , no charge coolers
That's mine
Rear radiator with no other coolers attached.
Turbo charged but do not know if it has intercoolers as I don't know what they look like
There is a large tank with a big metal hose going to the turbo. I am assuming that this is where the turbo gets it's air from, and I need to know if there is a BIG filter in there, and if there is I'm sure it needs to be changed. If it is really dirty would it affect the temperature?
I am going to take Brett's advice and put a new thermostat in. Does anyone have a Cat part # and a place in mind where I can get one, and what temp should I install?
I thank everyone of you for your input to this discussion I am really learning a lot here.
Rick
Check the air cleaner first,won't cost anything,you can get the thermostat(regulator) at a Cat dealer but they will want the engine serial number,look on Ebay you can sometimes find a parts book.Just looked,plenty of books and regulators,plus you will need all the associated gaskets.
Thanks John, I see a lot of parts books, but not sure they will cover my 1992 3208t motor. Most of them are from 1967-1974 and so on.
Rick
The cover of the book will usually state which serial numbers it covers,some Cat engines also have what they call an arrangement number.
Yes, the correct thermostat(s) would be specific to your engine serial number.
I would NOT try to order over the internet-- too much chance of getting a "designed to replace" of unknown quality. The internet is full of knockoff parts.
Said another way, GET THE CATERPILLAR CORP PARTS.
And, as several have mentioned, have you taken a strong flashlight and shined it on the front (from engine room) of the radiator.
BTW, very easy to determine if you have a Charge Air Cooler: Locate where the intake air goes into the engine. Follow that plumbing back. It will either go to a CAC OR it will go directly to the turbo.
There has been discussions on the Forum about REAR radiator Foretravel coaches, that originally came with fans that move air from outside rear to inside engine compartment. Some have improved cooling by replacing fan with one that has the blades curved differently so with the same rotation it now moves hot air from inside engine compartment to outside.
Drawing air in from rear of coach is also disadvantaged by the lower air pressure caused when driving down the road.
Agree, it makes no sense trying to pull air from the low pressure/high vacuum area behind the coach and "pulling it" forward against natural air flow.
Certainly no other rear radiator chassis do this.
Are you sure there are Foretravels that were set up that way (vs improper later fan installation)?
The intercooler has to be on the coolest side of the radiator or it defeats it's purpose. In other words, if the air goes through the radiator first, might as well take the intercooler off.
Pierce
Absolutely correct. The objective of an inter-cooler/CAC is to bring intake manifold temperature down to close to ambient temperature.
Hmmm now this poor old Cowboy/Preacher is plumb befuddled ! Am I right in assuming that the fan pushes air out rather than pulling it into and over the motor? If so, where does the cooler air enter the engine compartment from?
Yes, air goes from the engine room OUT THE BACK.
Lots of openings below engine for air to enter the engine room. Ideal, NO. Does it work on the majority of the diesel powered motorhomes on the road-- YES.
This large round item takes air from the outside and routes it to the intake on the turbo. My question is there a large filter inside this can and do I access it by taking the end off?
IMG_20220908_174722532
Yes, that is your engine AIR FILTER.
Sorry, no first hand experience with the U240 and Cat 3208.
Might remove the bolts in the picture and see if the filter element is removable.
If you have an AIR FILTER MINDER what is its reading???
Thanks Wolf I didn't want to take the wrong thing apart and have washers, bolts, and springs jump out at me 🤣
I will take the end off and see what is in there.
Rick
Can anyone tell me where to point the infared thermometer to check the engine temp against the dash temp gauge?
Rick
Rick,
While that is a valid question (and someone with more Cat 3208 experience will weigh in), not sure how relevant it is to your issue.
Much more important is that your temperature goes from "whatever" to high reading with the slightest extra load.
So, correcting the "limited cooling capacity" is the issue. That is why the suggestions of cleaning the front of the radiator and changing the thermostats. Both are inexpensive and can basically be considered Preventive Maintenance. Sure there can be other causes, but start with the basics.
The hose into the top of the radiator is a good bet for temp reading.
Did you verify that the shroud is in place ?
If the Tstat is faulty then it will overheat with any load.IMHO
Your temp issue seems to be load related and that points to thermal exchange problems . Plugged air flow at the core, shroud missing, wrong fan, loose belts, Small core even possible .
Understand you point. But if the thermostat fails to completely open, but does move from closed to "somewhat open" it will exhibit the same symptoms.
Were replacing thermostat/regulator not considered a part of routine preventive maintenance, might be a different priority.
True enough. And if the coolant has been rusty than the entire system is compromised .
Yup, and coolant change is also what most would consider part of routine preventive maintenance-- I sure do.
Back to your first post you mention the PO was chasing this problem also. If you followed the link in reply #3 combustion gas getting in the cooling system is easy to check. You can buy a litmus test kit cheaper than driving somewhere to have it checked. It is one of the first things I check on someone's over heating problems as it is so easy to do and I have the tester.
I check for combustion leaks by taking the hose that goes to the over flow tank and the hose in
a can of water start the engine and see it any air bubbles come out. You could get some but if it is
a problem the bubbles will come out steadily. It could not leak until the engine gets hot.
Ok, thermostat is ordered from the Cat dealer and will not be here until Thursday. Radiator has washed from the front and it is clean.
While waiting for parts arrive I took the BIG air filter out today, and I don't see how the motor was running at all, but it was and purred like a kitten.
I really don't think it has ever been looked at let alone replaced or even clean since the coach was new.
There was at least 6-8" of loose silt packed around the filter and in the bottom of the canister. The filter itself was fully plugged. Am trying to clean and also looking for a new one.
Rick
You really need to go through or have someone else go through the ROUTINE PREVENTIVE MAINTENANCE. Not doing so could end up costing you $$$$$.
Might have sounded like a kitten but get a new air filter and it will run like a Cat,that top cover should come off and there should be a part number somewhere,you can always get one from the dealer.Looking at that neglected filter I would change every fluid
and filter on your coach that you are unsure of.If you want to go all out,clean/wash the outside of the engine and transmission,
and grease all your grease fittings.
Rick,
When we bought ours, it was much worse as the wire mesh was under a quarter inch of dirt. It had a lot more power with a new filter. You have a mechanical engine so they really over fuel with a restricted air cleaner leading to overheating. Your radiator is probably just as dirty.
Pierce
When we purchased the coach (less than 2 years ago) we had the dealer go through and change all the filters and the fluids, and they all look still clean, Plus all the filters still look good.
I think there is the possibility that whoever did the work at the dealership was a real young man who had no idea in the world there was even an air filter, and it got overlooked.
On my way to the dealer this morning with filter in hand to see if they got one in stock.
Hope Pierce is right, this might be the reason for my overheating problem !!
Rick
Did you do a really good job cleaning the radiator? It takes a good cleaner to emulsify the dirt and oil that rear radiator, rear engine coaches get in the radiator fins.
Dealerships don't always do the work they charge you for. I remember Bill Chaplin marked some parts before taking his coach to the shot. Some of the parts were not touched but were charged for.
Pierce
A clogged air filter would certainly cause low HP.
Consider it good Preventive Maintenance.
STRONGLY suggest you review what exactly the dealer replaced/serviced. Post it line for line and we can give you what else needs t3o be done.
CERTAINLY, with the TORSILASTIC SUSPENSION, you need to check RIDE HEIGHT. It is adjustable (raised by removing the 1/4" thick shims). This can be critical for suspension and driveline wear.
Good explanation for clogged air cleaner causing high EGT. Lower power as less air but much higher cylinder temps. Clogged air filter = high pyro temps? | The Diesel Stop (https://www.thedieselstop.com/threads/clogged-air-filter-high-pyro-temps.242006/)
Quote: "OVERHEATING
In severe cases, a dirty engine air filter can cause or contribute to overheating. Like poor mileage, overheating is attributed to a rich-running engine. If your vehicle's engine air filter is clogged or otherwise dirty, less oxygen will enter the combustion chamber. As all the fuel burns in the combustion chamber, it can raise engine temperatures, potentially causing your vehicle's engine to overheat."
If you have a marginal cooling system, driving up to higher altitudes with a restricted air cleaner and especially a mechanical engine will cause higher EGTs. The radiator, radiator fan are already less efficient and there is less oxygen in the combustion chamber with more fuel so the temperature of combustion goes up. The restricted air cleaner will lessen the amount of oxygen but the injectors will still overfuel.
Pierce
Wowwwww, thanks for all that info Pierce, extremely helpful to this old dumb ex cowboy, now shade tree mechanic. After reading your article, I can see that my clogged air filter just might be my problem with over heating. I am still gonna change out my thermostat, and I power washed the radiator as well. That's why I love this forum, cause there is a world of knowledge hiding in all the heads of the people. This is better than paying to attend a college class any old day.
Pluss the guys on here are super helpful like Wolfe10.
Thanks again Pierce.
Rick
Be careful power washing the radiator. I like to use a liquid cleaner on it from a spray bottle and then gently hose it off. That us usually enough but if you have quite a bit of oil and dirt in it, it may take a couple of cycles.
Thermostats and a products of combustion test is also a good idea. A light headgasket leak can be cured chemically with one of many additive available at the parts store.
My Porsche turbo has 6 cylinders but has a 7th injector so when to boost comes up, a sensor turns on a steady spray out that injector to cool the combustion. Then, I get a bit of black smoke out the exhaust. In a diesel, it would do just the opposite as far as temperature goes. A gasoline engine needs about a 14 to 1 air to fuel ratio, whether at idle or wide open throttle. A little leaner than that is good for emissions but the temperature in the combustion chamber goes up. That's why a diesel race car like the Le Mans winning Audis has such an advantage. Under a yellow flag, they can cruise around the track at lower speeds and a higher air to fuel ratio saving lots of fuel.
In a gasoline fueled aircraft, when you are at cruising altitude, you usually peak the EGT with the mixture control and then lean the mixture just above the point where the engine starts to run rough. Some may peak the EGT and then go rich until the EGT drops. Depending on a Lycoming or Continental engine, you only have a recommended 6 or 8 seconds at peak to find the EGT you are looking for. I have 10 to 1 pistons so most of the rebuilders don't recommend going to rich of peak EGT.
So, unless you have a leaking head gasket, installing a clean air cleaner may reduce the temperature in the cylinders a little and drop the temperature slightly. If the head gasket is leaking or thermostat is failing, it will continue to run hot.
An engineer on our fire dept drained the coolant from our Crown (brand) squad but forgot to refill it. Naturally, it overheated and the head gasket leaked when filled with coolant. We used a chemical head gasket additive and that totally fixed it without any further problem.
A further possibility: Quote: Blockage from the air coming out of your engine can cause overheating in the cylinders. The first thing you should do is a thorough visual inspection of the exhaust system. This should include the visible and internal elements of the exhaust piping. If you find no blockage in the exhaust piping, the next place to check for restriction is in the muffler. Ensure that you check the airflow exhaust pressure coming from the engine. If the airflow is less than the minimum amount allowed by the OEM, it means there's a blockage higher in the exhaust system."
Pierce
Did the REv verify the OE shroud is in place?
Just for nuthin', but have you weighed your coach when you are fully loaded? We began our Foretravel with very good friends of ours and had identical coaches. 1993 U225 36' with Cummins engines. We never had problems with overheating, and he regularly did. He added a second radiator, a thingy that sprayed water on the radiator to help cool things, and STILL had problems in high temps. He was also a fix-it guy who had every tool you can think of and a back-up. I suggested that he weigh his coach, but he didn't want to because that might mean he had to leave some stuff at home! At some point he was forced to take his coach for some repair and left a great many things behind to avoid having them "appropriated" by mechanics he did not know. Whaddya think??? No overheating! Just my 2 cents.
He still won't weigh his coach.
Carol,
Good seeing you put in your two bits worth! With a marginal cooling system, weight may be a factor with just thermostat temp in gentle terrain and 3 seasons but getting hot in summer. Ours is great until the outside temp goes up followed by the engine temp when the coach sees a hill. In summer, I have to drive here in the mountains with almost empty tanks to try to keep the temp below 200°. We are not full time so travel lightly loaded. Hate to think what it would be like otherwise.
The twin fans on ours eat up close to 60hp at high fan speed and climbing a grade always means high fan speed. Imagine how much additional heat the engine makes supplying the horsepower to the fan system. In essence, the hydraulic fan system cools the engine while heating the engine at the same time. What an incredibly stupid idea.
For those used to cars, a diesel does not have a throttle plate so air from the outside is unobstructed from the air intake to the intake valves or ports. No vacuum created here so cars with power brakes have a vacuum pump fitted to the engine. The foot throttle just moves the lever on the injection pump or unit injectors. With an electronic engine, the ECU controls the amount of fuel the injectors spray and how long they spray it.
If you do have marginal cooling, it will only get worse the greater the altitude you are driving at.
Pierce
Yes it is, and we'll sealed.
Rick
Hey Pierçe, what kind of àdditive àre you talking about for a head gasket leak?? Jus wonderin
Rick
Go to this Amazon page and make sure to read all the reviews. Your local parts store may have the same stuff. RV cooling systems hold a lot more so need more additive.
Amazon.com : head gasket sealer (https://www.amazon.com/s?k=head+gasket+sealer&ref=nb_sb_noss_2)
Pierce
But, do not add a head gasket sealer unless you have verified that you do have a head gasket leak and that it is minor enough that the sealer is likely to fix it.
Said another way, you really need to diagnose the root cause(s) of your overheating and fix them.
Agree, many times a sealer has blocked heater cores and a percentage of the radiator.
Yes, you have to check for products of combustion in the coolant before thinking adding anything as stated in my first reply. But, that's easy to do. Most additives I've seen won't clog the radiator or heater core and designed for headgaskets not radiator leaks. They contain no solids of particulate matter. Watch the reviews on YouTube for all the sealers available.
Testing the coolant for products of combustion and getting a positive result does identify the root cause of overheating..
Also, check your oil dipstick for signs of coolant in the oil. The oil will usually have a gray color to it.
https://www.youtube.com/results?search_query=head+gasket+sealer
Pierce
Well lo and behold my BIG air filter arrived today, so will put that in today or Sunday afternoon. Would like to make a 150 mile run up to the VA in Prescott Tuesday. Thermostat on back order, should get it next week for sure.
When I check the oil I will look carefully to see if has any water in it. There sure are a lot of diff kinds of head gasket sealer. I will read the reviews, but I would trust any info from someone on this forum a lot better than any reviews on Amazon.
Y'all have a safe and blessed weekend
Rick
You can also check for combustion pressure/ leak into coolant, by topping the coolant with the cap off to the rim and watch for bubbles. Bubbles bad .
You know Brett I would love for the coach to ride higher, is there a way for me to adjust it?
That's a good idea Mike, thanks for the suggestion.
Rick
Of course (if you have ride height shims left).
Park on level pavement, jacks up/stowed.
There is a horizontal area behind each wheel position that forms the top of the wheel well. Measure from there to the ground. Record the readings at each wheel position. It will be the only area that measures somewhere between 30 and 33". Tell us.
Then at the front and back of each wheel positions are the long bolts that hold the torsilastic shackles. Count the number of those 1/4" thick shims at each wheel position (should be the same number in front of and behind each wheel position). Tell us.
Then we can go from there.
I have done the adjustment many, many times with hand tools only.
But, please post your results in A NEW TOPIC so we can keep it separate from this overheating discussion.
Ok, installed the new air filter, checked the oil. Oil looks really good and clean, radiator is up into the neck with clean and a green cooler. There is a surge bottle and it is empty, will fill it with antifreeze :tomorrow and take for a ride into Quartzite to check the temperature!
This item is mounted to the side of radiator, does anyone know what it?
Rick
Rick,
Your pic. didn't load so try again as there are several things that it could be on a 240.
Mike
Here it is, finally loaded
Hydraulic reservoir.
Should have a sticker on it saying what fluid. Likely (please verify) Delo 400 15-40.
Again, strongly suggest you have someone knowledgeable go through your coach with you. Could save some very expensive repairs.
"Again, strongly suggest you have someone knowledgeable go through your coach with you. Could save some very expensive repairs.
More...1 Likes"
Thanks once again Brett, I'm not sure what the hydraulic fluid is for.
I live where it is 130 miles to Yuma, 142 miles to PHX, and 114 to Lake Havasu, so I have no one to walk through my coach with me. I apologize for so many questions. I'm just gonna park this coach down by the horse stalls, and then This Winter I will go down to the Foretravel incampment South of Quartzsite and find out more.
Thanks Brett and everyone else that were so thoughtful to help this OLD DUMB Cowboy, I really appreciate your suggestions and input.
God Bless Y'all
Rick
The hydraulic reservoir is likely for your power steering.
Someone with first hand experience with the Caterpillar 3208 could direct you to the pump and you could follow the line from reservoir to pump then forward from the pump.
Steering only on n mine.
Mike, do you have that same kind of can attachment on the side of your radiator?
Rick
Ric,if you can hold out till Jan you will have bookoo Foretravlers to look at your coach,many of us will be at desert palms in Salome
I will be happy to come and help.
Yes. supplies hydraulic oil to the PS pump.
Thanks Mike. Standing at the back of my coach looking at the radiator there are three dip sticks, 2 on the left and one on the right. Can someone please tell me what each one is for?
Rick
Pull each and look at the fluid:
Hydraulic should be clear and likely motor oil. Likely on the reservoir you were asking about.
Transmission will look and smell like ATF and will be LONG.
Engine oil will be black oil.
But, not difficult from above (bed open) to follow each one to its origin.
Got it Brett, thanks
Rick