5 shops later and no resolution. Are they really running diagnostics? I need someone think outside the box…
205,600 miles.
Chronic problem for 5 years.
Replaced the waterpump & thermostat 3 or 4 times. Hoses & cap too.
Radiator replaced 2005.
Catalytic converter & muffler replaced 2005.
New exhaust manifold gasket in 2007.
Last waterpump, heater hose, thermostat & gasket, valve cover gasket done in June 2009.
Engine flushed March 2010.
My most recent overheating spell began in late March. Only heats up on 70+ degree days, on highway 55mph+. Cools on idle.
The first shop recommended radiator flush-done, still overheats.
Second shop said replace the thermostat.
Third shop said no problems, try thermostat-replaced, still overheats.
Fourth shop, fourth time I got, “…can’t get it to overheat, bring it back on a warm day” They suggested there may be CO in the cooling system.
Fifth shop- Crysler- same response, and they changed the radiator cap. Said the radiator temp varied by 20 degrees in various spots, but system was ok. ???
I smell oil burning. It has been 3,000 miles since my last oil change and the oil looks very clean. ???
Noticed a decline in gas mileage for the past 6 months.
OK. This may sound like a funny question but is the engine “really” overheating? A bad temperature sensor or temperature gauge may make you think the engine is overheating when in fact it’s not.
Is your shroud and fan clutch in good order?
Does running the heater while the alleged overheat condition is in progress relieve the temp. Does it put out adequate heat?
Let me add that in spite of my questions, you should not even need a fan at anything other than lower speed usage. I have no mechanical fan on my 2002 Wrangler. At highway speeds the ram air is enough to cool the engine. I set my fan setpoints via the gauge and it never reaches them except in urban traffic (stop lights, etc.).
Thanks for the reply!
Fan may be an area to check (which no one has addressed). Last summer I started the car, heard a loud metal schreeching noise, shut it off, and found a kitten on my engine block.
The fan will turn, but not freely. It will turn 1/4 turn when pushed.
It runs, but not very fast in my opinion; especially when it gets to 235 degrees.
What is the shroud?
Is the fan mechanical (attached to the front of the engine) or electrical (electrical lines going to it)? The shroud is the plastic that surrounds the fan to direct the air. It won’t spin fast, if mechanical, when you are in a position to see it.
If the ignition timing is out even a few degrees it can cause engine overheating and it is the last place you are likely to look for a problem you think is in the cooling system.
This is unlikely but you wanted “outside the box” A 92 Dodge minivan was donated to our Pastor. It overheated only between 45-60 mph. We had the service records and they looked much like yours but the previous owner was on vacation and could not be reached. It turned out that the electric radiator fan was running backwards. Below 45 it was pushing enough air through the radiator to cool and above 60 the air coming in overpowered the fan enough to cool
We later found out tht the van had been hit in the left front and in the repair someone had re-spliced the fan wires backward.
The fan will turn, but not freely. It will turn 1/4 turn when pushed.
The fan should turn freely but with resistance due to the fluid clutch mechanism. It’s the finned thing that the fan is attached to. Yours sounds like it needs replacement. In your case I’d say that the fan is inhibiting flow through the rad by not unloading at higher speed. That’s an obscure possibility, but as I said, your Wrangler should require no fan at all at highway speeds.
interesting, will look into it… thanks!!
Thanks for your reply! The timing was checked last June, will check again.
Yes, turning the heat on will releive the temp 10 - 20 degrees. Heater blows hotter on the road, cool on idle (but that’s how it has always been for the Jeep).
It is mechanical. So that explains why it doesn’t turn freely. Thanks!
New info on 95 Wrangler-
I got someone with problem solving skills to look at my Jeep. As he suspected, it is not overheating.
We changed the temperature sensor to the gauge. The gauge is still reading hot (235 degrees), the hottest spot under the hood is where the heater hose connects to the engine & waterpump (200 degrees).
We will be changing the temperature sensor that attaches to the waterpump and see what that does.