Maybe we can help John out. (from AirstreamList)
-Fred
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Subject: 370LE (Ford 460) engine overheating
My 1989 370LE has been in and out of the shop all summer with a still-unsolved problem with engine overheating. The engine is a Ford 460 with 14,000 original miles. No prior modifications to any
engine/drive component. Everything worked well prior to this
problem. The shop has done all of the obvious repairs and checks
(radiator cleaning, check/replace belts and hoses, replace sender and dash gauge and validate readings with heat gun, check water pump, timing, fan alignment, replace fan clutch, etc.), but nothing seems to solve the problem. The engine itself has passed all of the usual checks, including chemical analysis of the oil, compression checks, without any problems. This problem is new this year, and it came suddenly. The shop is now looking for an auxiliary fan system to supplement the factory system. Has anyone seen/solved a problem of this kind? I will appreciate any information.
Fred--Thanks very much. I will try Airstreamforums.com. The exhaust system has (if I have the term right) flow-through mufflers, which Airstream told me were original with the Ford engine. I have talked with Banks and one other supplier (Thorley? not sure about the name) about an aftermarket kit, and the response has been that none is available now. I
talked with the owner of another 370, and learned that he has a Banks system that was installed about 10 years ago. So I think I am out of luck on Banks. I have asked the garage to research available open muffler systems to see whether or not one might improve things. My driving speed is a pretty steady 55-58 mph, largely because I am more comfortable driving the 370 at this speed than at higher speeds. My transmission has overdrive. One of the mechanics speculated that the engine might be
slightly more comfortable at 65 because of the gearing. If you have additional thoughts on any of this, I will be grateful to know them. And I am passing on these suggestions to the garage manager, who has come to see this problem as his personal crusade.
Advanced timing/lean mixture, but driveability issues also
Inlet hose from radiator to water pump collapsing (mainly a BB Chev problem, but.../thermostat installed backwards
Either of these should be indicated by little or no flow with the radiator cap off at operating temperature. Has anyone run the engine to operating temp. and checked flow?
Fan/shroud not properly installed. Shroud must be tight against the radiator, fan inside the shroud and 1/2" clearance between fan and shroud (approximately)
Radiator cap pressure rating correct.
Pressure leakdown test to check for cracked or warped head or bad head gasket. Might also get an indication of this by bubbles in the coolant with the cap off and engine running.
I would start by pulling the radiator cap and seeing if there was any coolant flow when the engine had made it to the opening temp of the thermostat. You could then isolate it to air flow or coolant flow.
Here's a follow-up (from AirstreamList)
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The report today is that my engine now shows signs of serious damage from the overheating, and ought to be replaced. I am waiting for a second opinion from another shop, but the evidence today seemed pretty clear. My inquiry brought great advice from this group. Thank you for that. With any luck, perhaps throwing a lot of money at the problem now will get me back on the road in the fall.
Hi John
Take a look at the impeller on the water pump. A way to check this without dismantling the engine is to run it to normal temperature and turn on the heater. If the impeller has failed you will get no heat out of the heater because the water is not circulating. If the engine is really in poor conditon and I owned it it would be a natural for a 5.9 Cummins. The water pump will appear to be ok from the outside and still have failed.
Joe
F--Back in August, you very kindly provided information for me at a time when my 370LE's engine was overheating. Various bits of advice came also from a web site to which you referred me. This is to thank you for helping, and to let you know that the 370LE has come back from repair and seems to be fine.
In the end, the second opinion on the problem ruled out a new engine as a remedy. Similarly, both shops argued against trying to install some other kind of engine, diesel or whatever, because of the scale of the necessary changes. Instead, the fix was to install a four-core radiator with a spacer between the engine radiator and an auxiliary heat exchanger mounted in front of it, then to add a pair of electric auxiliary fans between these two units.
There are both thermostatic and manual switches to control this system, which kicks in automatically either when the AC is turned on or when the engine temperature reaches 210. Several other modifications were made at either Ford's or Airstream's suggestion--new water pump of a different design, improved thermostatic clutch on the primary engine cooling fan, modern air cleaner, larger oil pan and sump, and some other things.
I don't know how to judge the value of each of these changes in the whole equation, but a day of hard driving on mountain roads produced no operating temperature above 201 on either the dash gauge or a digital heat sensor. On all but the most severe grades, the engine operates at its set temperature of 190. The engine is smoother and quieter at all speeds and under all loads than it has been since I bought the Airstream, and it passed various tests of the engine's condition (compression, oil chemistry, etc.) with no problems. For some reason, gas
mileage is somewhat better than it was before, but I don't expect this gain to last. I appreciate very much your advice on this problem.
Best regards, J
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I am glad John got this resolved. I hope this information will help someone else down the road. -F
Have you considered making the doghouse out of lexan so you can showcase the engine ater the interior is complete. It is a shame to have all of that hard work hidden under a plywood box
__________________
Brett G
WBCCI #5501 AIR # 49
"Stop worrying about the potholes in the road and celebrate the journey." -- Fitzhugh Mullan
Wise men talk because they have someting to say; fools, because they have to say something. -- Plato
In politics, absurdity is not a handicap— Napoleon
I know it is not a motorhome but a year or so ago one of my work trucks, a 91 F-350 dually with the 460, had started overheating. I went through all of the usual, radiator, t-stat, water pump, fan clutch, etc, etc, until one day I decided to check the catayltic converter. Bingo!! The core of it had broken loose and was jammed in the outlet sideways, acting like a stopper. It runs much cooler and no more heat soaked starters as well.
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No wonder it needs two 18" fans!
Oscar
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