Overheating continues

[wolfe10]

I am having a similar problem. Replaced the top overflow tank, water pump, thermostats new long life coolant and it's still overheating under load. Question. The fan air control switch seems to be disconnected by the previous owner. Why would he do this? Fuel economy? I'm focusing on the fan for now. Any advise would be greatly appreciated.

Please tell us exactly what coach you have and what engine.

Many of those here have direct drive fans, so answers could be all over the board without knowing what you have!

[Sharongeti]

Hi Brett. It's a 2000 38' Serengetti 3126b Alison tyranny.
I have ordered a new solenoid switch for the Bendix fan clutch. Hopefully this will work. I'll keep you updated.
Thanks! Greg

[Glenn]

Hi Greg,
As Brett mentioned, most of us have the direct belt drive fan so we aren't familiar with the fan clutch you have. If you can provide us with your engine serial number we should be able to look it up on the CAT parts website. If the fan clutch was originally supplied by CAT, the parts should be listed and that would give us a better idea of what you are working with.

What I can tell you from personal experience is that if the fan isn't working at all these engines will overheat in short order, even at idle. Since you stated that you only experience overheating when the engine is under heavy load, that would indicate the fan is working, at least to some extent, and there may be another problem.

One of the more common problems rear radiator engines is the buildup of dirt and grime on the Charge-Air-Cooler (CAC) and radiator restricting the air flow. Very easy to check, just look at you fan blades. Are they white plastic, or black with grime. If they are black, rub you hand across one. If your hand is now black with grime, so is you CAC and the forward side of your radiator. The forward side of your radiator is behind the CAC where you can't see it. If you do need to clean the grime from the CAC and radiator, remove the fan for access, steam clean or pressure wash from both sides several times. The CAC fins are sturdy enough that you won't damage them but very careful not to damage the radiator fins if you are pressuring washing. Dishwasher detergent mixed with water, or Simple Green, can help loosen the grime. Engine degreaser foams up on the surface and doesn't penetrate into the fins so it isn't as effective. Clean the fan blades as well to increase its efficiency.

When reinstalling the fan, make sure its the right direction. The blades are curved like a wing. the convex side faces the engine, the concave side faces the CAC. They have been found installed backwards and this will reduce their efficiency.

The primary source of grime is the breather hose from the engine. The original breather hoses ended forward of the fan so any oil drips from it was sucked into the fan. If your hose hasn't been extended, add an extension hose so any discharge from the hose is well behind the fan.

[Ozium]

With an air-operated fan clutch, the air is used to release the fan clutch(free spin).
At 23 years old I would check the clutch first.

***Please only do this if you feel comfortable.***

Disconnect the air line from the clutch(either at the clutch or solenoid)
Using a broom handle or equivalent have the engine running and slowly put the broom handle into the fan blade and see if the fan stops spinning.
If it fights you back then you know the clutch is working, if you can stop the fan then it is time to replace the clutch.

Again

***Please only do this if you feel comfortable.***

The guide above is a definitive way to know if your air-operated fan clutch is working.

You can also just rev the engine and listen to see if the fan is spinning faster but this can be misleading
Also when you first start the engine up from cold the fan should stay engaged until the air system charges up or the engine is using the fan as a load to help it warm up quicker and will turn it off after a few minutes.
Considering you are replacing the solenoid I don't think these last steps will be applicable to your situation.

[wolfe10]

I will reinforce the advice to clean the front of the CAC once a year on any rear radiator configuration coach.

PERIOD.

If you want to check. use your phone/camera to take a picture of the front of the lower part of the CAC. That fan is a vacuum sucking up all kinds of crap off the road and the front of the CAC "filters" it out. Hard for cooling air to get through the dirt.

[Sharongeti]

Thanks for the help! I'm all over these solutions!

[TDJohn]

What is the year, make, and model of your coach? What engine does it have? With out this type of basic, but critical info, we are not able to help you.

This is a friendly helpful reminder to the members that have not done so. Please, please, put your coach info in your signature, as it helps and saves time for the ones trying to help you. Please see my signature or other signatures as an example of what should be included to help us all. Thank you!

[Sharongeti]

Problem solved! It was the thermal switch. I drained about 4 gallons of coolant and removed the 2 wires. Unbolted the old one and put in the new one. Temperature is holding under 180.
Thanks for all the input!

[keegan8]

Overheated with the FORD, found on the road dead, plastic tank,

Replace with https://www.fsrproducts.com/shopping/pr ... 71&c=13492, new coolant and flush.

And as others have stated,,, Clean the CAC and radiator. Simple green for Aluminum. Tons of dirt and oil came out of it. Garden hose didn't cut it. Neighbor is a 40 yr auto repair owner, used the power washer on low, only up and down, cleaned it out and didn't bend any fins.

Drove it today up hills in 6 sp, its hot, dash A/C on full, for an hour. No overheating, stayed between 170 and 190. And replaced both caps which didn't pass testing.. Get the pressure kit at O'Reily Auto, its free.

PS, Remove the fan blade, four bolts, lay some plywood down on top of the bed area, and lay chest down to wrench that bastard out, much easier to clean the CAC that way. And clean the the blade, it was full of crap also.

[keegan8]

oh yeah, extended the slobber tube also.. Who the hell called it the "slobber tube" ? That a Safari term? lol It does slobbers oil