Overheating 1992 U240 with Cat 3208

Topic: Overheating 1992 U240 with Cat 3208 (Read 2029 times) previous topic - next topic - Topic derived from 94 8.3 Cummins overhe...

Re: Overheating 1992 U240 with Cat 3208

Reply #25 – September 09, 2022, 05:36:17 am

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

Re: Overheating 1992 U240 with Cat 3208

Reply #26 – September 09, 2022, 07:03:05 am

The cover of the book will usually state which serial numbers it covers,some Cat engines also have what they call an arrangement number.

Re: Overheating 1992 U240 with Cat 3208

Reply #27 – September 09, 2022, 07:45:40 am

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.

Re: Overheating 1992 U240 with Cat 3208

Reply #28 – September 09, 2022, 01:55:53 pm

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.

Re: Overheating 1992 U240 with Cat 3208

Reply #29 – September 09, 2022, 02:01:10 pm

Quote from: Barry & Cindy – September 09, 2022, 01:55:53 pm

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)?

Re: Overheating 1992 U240 with Cat 3208

Reply #30 – September 09, 2022, 03:36:12 pm

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

Re: Overheating 1992 U240 with Cat 3208

Reply #31 – September 09, 2022, 03:37:44 pm

Quote from: Pierce & Gaylie Stewart – September 09, 2022, 03:36:12 pm

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.

Re: Overheating 1992 U240 with Cat 3208

Reply #32 – September 10, 2022, 01:50:07 pm

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?

Re: Overheating 1992 U240 with Cat 3208

Reply #33 – September 10, 2022, 01:59:02 pm

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.

Re: Overheating 1992 U240 with Cat 3208

Reply #34 – September 10, 2022, 06:12:35 pm

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

Re: Overheating 1992 U240 with Cat 3208

Reply #35 – September 10, 2022, 06:15:54 pm

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???

Re: Overheating 1992 U240 with Cat 3208

Reply #36 – September 10, 2022, 06:56:26 pm

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

Re: Overheating 1992 U240 with Cat 3208

Reply #37 – September 11, 2022, 11:41:38 am

Can anyone tell me where to point the infared thermometer to check the engine temp against the dash temp gauge?

Rick

Re: Overheating 1992 U240 with Cat 3208

Reply #38 – September 11, 2022, 11:46:52 am

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.

Re: Overheating 1992 U240 with Cat 3208

Reply #39 – September 11, 2022, 02:36:33 pm

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 .

Re: Overheating 1992 U240 with Cat 3208

Reply #40 – September 11, 2022, 02:39:06 pm

Quote from: Protech Racing – September 11, 2022, 02:36:33 pm

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 – September 11, 2022, 02:42:34 pm

Quote from: wolfe10 – September 11, 2022, 02:39:06 pm

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 – September 11, 2022, 02:43:36 pm

Quote from: Protech Racing – September 11, 2022, 02:42:34 pm

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 – September 11, 2022, 02:51:17 pm

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 – September 11, 2022, 08:13:19 pm

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 – September 12, 2022, 04:25:49 am

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 – September 12, 2022, 06:52:45 am

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 – September 12, 2022, 06:58:57 am

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 – September 12, 2022, 10:18:39 am

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 – September 12, 2022, 02:51:20 pm

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

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