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Topic: Overheating 1992 U240 with Cat 3208 (Read 2979 times) previous topic - next topic - Topic derived from 94 8.3 Cummins overhe...

Re: Overheating 1992 U240 with Cat 3208

Reply #40 –
Quote from: Protech Racing –
If the Tstat is faulty then it will overheat with any load.IMHO

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.

Re: Overheating 1992 U240 with Cat 3208

Reply #41 –
Quote from: wolfe10 –
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 .

Re: Overheating 1992 U240 with Cat 3208

Reply #42 –
Quote from: Protech Racing –
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.

Re: Overheating 1992 U240 with Cat 3208

Reply #43 –
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.

Re: Overheating 1992 U240 with Cat 3208

Reply #44 –
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.

Re: Overheating 1992 U240 with Cat 3208

Reply #45 –
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

Re: Overheating 1992 U240 with Cat 3208

Reply #46 –
You really need to go through or have someone else go through the ROUTINE PREVENTIVE MAINTENANCE. Not doing so could end up costing you $$$$$.

Re: Overheating 1992 U240 with Cat 3208

Reply #47 –
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.

Re: Overheating 1992 U240 with Cat 3208

Reply #48 –
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

Re: Overheating 1992 U240 with Cat 3208

Reply #49 –
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

Re: Overheating 1992 U240 with Cat 3208

Reply #50 –
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

Re: Overheating 1992 U240 with Cat 3208

Reply #51 –
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.

Re: Overheating 1992 U240 with Cat 3208

Reply #52 –
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

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

Re: Overheating 1992 U240 with Cat 3208

Reply #53 –
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

Re: Overheating 1992 U240 with Cat 3208

Reply #54 –
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

Re: Overheating 1992 U240 with Cat 3208

Reply #55 –
Did the REv verify the OE shroud is in place?

Re: Overheating 1992 U240 with Cat 3208

Reply #56 –
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. 


Re: Overheating 1992 U240 with Cat 3208

Reply #57 –
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

Re: Overheating 1992 U240 with Cat 3208

Reply #59 –
Hey Pierçe, what kind of àdditive àre you talking about for a head gasket leak?? Jus wonderin

Rick