Need an overheating expert/master

[91SHOInterceptor]

I have had my SHO for almost 5 years now and work on it alot so this problem has got me. I cant figure out whats wrong with the car overheating. I havent driven it much but I cant seem to determine the cause.

Problem: The car overheats mostly while at idle. It still gets hot while driving and stays near the "R" and "M" when driving. If I let the car sit at idle for awhile, the guage goes all the way to and alittle past the "N". The engine light never comes on. Long drives it stay pretty much in the middle but heats up quickly.

The oil light also flickers while the car is at idle, BUT only when it has been running for quite some time. I drive and it goes away. There are NO oil leaks anywhere. There is plenty of oil. I probably have to replace the oil pump since it wasnt during the rebuild.

I replaced the double core radiator, new reserve coolant tank, new thermostat with gasket, new upper and lower radiator hoses. The water pump is about 2.5 yrs old and looked good during the engine rebuild this winter. I replaced the radiator cap as well. Both temp sensors were replaced also. The fan DOES come on at the default temp.

Other Symptoms: Coolant sometimes leaks out in between the water manifold and the thermostat housing. I took that apart and replaced it with another new gasket. It still leaks at times. The upper radiator hose gets really pressured and you cant hardly squeeze it at all unless you release the pressure from the radiator cap. No other coolant leaks can be found. Heat core works fine. There is coolant flowing through it just fine. There has been no coolant in the oil at all.

I am up for any suggestions. It might be a faulty head gasket but I want to be sure before I start going that route. What other things can point to the faulty head gasket? Any other suggestions to try figure this out?

I have several more parts just waiting to be bolted on to increase its performance but dont want to be tempted to push it until I figure this out. Any thoughts, suggestions would be greatly appreciated. Thanks

 

[pete c]

definitely sounds like a head gasket to me. Sounds like you have exhaust gases leaking into your coolant.

Run it with the rad cap off. Rev the motor and watch for any bubbles.

Why was it rebuilt? I assume this includes head gaskets. Were good quality gaskets used? Was it properly torqued? Were the head bolts replaced?

I think the head bolts are the type that need to be replaced if the head is removed. Seem to remember reading something a while back concerning this.

You could do a search on head bolts to confirm this.

 

[SHOtimer]

Your oil light flickering at idle is indicating low oil pressure, which is a symptom of worn rod bearings. Easy to replace and good insurance, would be a good idea to do that soon, especially since you are getting that light.
Doug

 

[ATXSHO]

Could it be the thermostat? Maybe it's not opening and causing the upper hose to get so pressurized it's hard to even squeeze and is also the reason you have coolant squeeze it's way out from the built up pressure. You did mention it leaks out there, right? May be just a bad (new) t-stat. shrug Have you checked you coolant level? I don't know, but maybe your coolant light is out and not coming on to warn you. I know sometimes when I drained my coolant and replaced it to the cold mark when the car was off, a day or two later the light would pop up and say it's low and it sure was. I did it another time and it was low after it did a cycle or two afterwards. Good Luck.

<small>[ May 14, 2003, 02:02 AM: Message edited by: ATXSHO ]</small>

 

[SHOZ123]

If you are using a 5w30 I would go up to a 10w as far as the oil light is concerned. Are you sure your coolant temp gauge sender and ECT sender are working properly?

 

[Stoney]

this may seem dumb but take a look at your oil cooler maybe clean it real good or see if its clogged or something? may be the oil not the coolant heating up

 

[BeatDaSHO]

WOW!!!!.....you are now the first person with the SAME EXACT problem as me. wahooooooo. I can not figure it out either. I have replaced EVERYTHING in the coolant system and nothing has changed. The water pump is about 7,000 miles old. I am HOPING that the impeller is worn down or something causing the coolant to not flow as fast. Finally someone else has the same problem as me. To cure this problem, I bought a fan relay from pep boys that kicks the fan on at a certain temperature. This makes the temp stay between the R and M at all times. But the temp used to hang around the L. If you figure out what the problem is, please email me at [email protected] Thanks.

Greg

 

[yamahaSHO]

SHOZ123:
Are you sure your coolant temp gauge sender and ECT sender are working properly?

Thats what I was gonna say

 

[BeatDaSHO]

I replaced my ECT and senders. I also did a leak down test and it's not a bad head gasket or else it would have leaked during the test.

Greg

 

[SHOZ123]

So just how hot is the coolant when it is at the N on your car? At what point does the cooling fan come on?

<small>[ May 14, 2003, 10:40 AM: Message edited by: SHOZ123 ]</small>

 

[projectSHO89]

Have you replaced the lower radiator hose yet?

Steve

 

[BeatDaSHO]

I don't know about 91SHOInterceptor, but i replaced EVERYTHING from the coolant system and that includes the lower radiator hose. The coolant temp at the N is at about 225 degrees and the MTX's should run at around 180-185 or so.

Greg

 

[91SHOInterceptor]

I cant reply with what I have done right now.. Im in between jobs at the moment. I will explain it all later when I get off duty later tonight. Thanks for the info though.

Sean

 

[91SHOInterceptor]

I did the 3.2 MTX swap... so I rebuilt the engine. I had a friend, who knows more about the car than I do, redo the block with the exact specs with new everything. New rod bearing were installed.

I replaced EVERYTHING as far as the coolant system. I have plenty of coolant... all new sensors, thermostat, hoses.. as I said in my first post.

I did NOT replace the oil cooler or the oil pump so those could be part of the problem as far as the oil light coming on. I would rather check those first before going to the rod bearings. I am also running 10W-40.

All the gaskets I used were from Josh T. I used ford parts were I could. I recall seeing any bubbles with the cap off and reving the engine. Any other symptoms that could point to a faulty head gasket? Thx

 

[SHOck]

Leakdown and compression tests will identify cracked head, block or leaky head gaskets for competant mechanics.

Is your fan coming on but the engine continues to heat up at idle? If so, you need to determine if you've got both good coolant flow and good air flow through the radiator. Is it overheating when the A/C is off? Is there anything stuck between the Condensor and the radiator? Have they ever been cleaned? Does the radiator fan appear to be moving at a decent speed? Try manually engaging high-speed fan operation and see what it does.

Oil pressure is going to fall as it heats up, this is a physical property of oil. You may not have a pressure problem. You need to check oil pressure at normal warm idle with a real guage. To know what is going on. The low oil pressure light is not a very useful guage, and yours could be off due to age.

 

[SHOZ123]

The oil cooler if it was sitting exposed is easily clogged by spiders and things. This happened to the one on my V8 motor I bought.

You can also get a coolant fan controller to turn the fan on sooner. Water wetter works good too. I assume the temp problem is only at low speeds?

Unless you take an actual temperature measurement on you car you cannot be sure what the gauge indicates. If you have changed the sender the gauge can still be out of "calibration". The only sure way to know what temp the coolant is, is to measure it with a thermometer that actually reads in degrees.

<small>[ May 15, 2003, 08:57 AM: Message edited by: SHOZ123 ]</small>

 

[220ksho]

Ok, I've read all the replies and all your info. There are two symptoms that you have that correlate with eachother, and lead me to believe that there may be something wrong with your radiator.

You said that you have a leak at your thermostat housing, and you've replaced that gasket (thermostat rubber gasket?) You also said that there is so much pressure in the upper rad hose that you can't hardly squeeze it. This should not be the case. This does indicate, however that water is flowing through the engine ok, which means your head gasket/heater core/etc... are fine.

I'm really leaning toward some sort of obstruction in the water path starting at the upper rad hose to radiator and beyond.

I don't believe the oil light flickering is related to your overheating problem. It is odd though. Did the oil pressure sensor get replaced with the rebuild?

Couple of things to help diagnose:

1. Remove rad cap. With your car idleing and begining to overheat, feel the temp of the water. Also monitor its movement. If your temp gage is up to the N or O, that water should be extremely hot(untouchable). If it isn't, there's a blockage somewhere between and including the t-stat and rad. If you find this to be the case, drain a decent amount of fluid from the rad by disconnecting the lower rad hose. This will drain it more aggressively than using the drain ****. Start the car cold and add fluid as needed.

2. Another thing to check... (This is probably not the case, but something that happened to me.) When I replaced my fan/motor assy, I had to rewire the connector because is was different and wouldn't plug in. I wired it backwards so the fan spun the wrong way and caused me to overheat. Should be blowing toward the motor. Also verify that the fan speed is vigorous.


How's your power? Normal? I don't think you have a MAJOR problem, just a minor one that's annoying and sucks, but part of the rebuild process.

Let me know.

 

[Ishodu]

Why don't you get a few cheap aftermarket gauges like sunpro or something. Install them under the hood temporally. That way you can tell us what they actual water temp and oil pressure is.

 

[BeatDaSHO]

I hooked up a gauge to mine and it was getting up to 220 degrees when before it would get up to about 190 tops. Even though I have the fan relay to turn the fan on, it's still "jigga rigged" and I would like to find out the cause of the 220 degrees.

Greg

 

[haydenm315]

BeatDaSHO:
WOW!!!!.....you are now the first person with the SAME EXACT problem as me. wahooooooo. I can not figure it out either. I have replaced EVERYTHING in the coolant system and nothing has changed. The water pump is about 7,000 miles old. I am HOPING that the impeller is worn down or something causing the coolant to not flow as fast. Finally someone else has the same problem as me. To cure this problem, I bought a fan relay from pep boys that kicks the fan on at a certain temperature. This makes the temp stay between the R and M at all times. But the temp used to hang around the L. If you figure out what the problem is, please email me at [email protected] Thanks.

Greg

On warm days my car will sit around or a bit below M when on the highway. In city traffic it will get up to the bottom of the O before the fan kicks on and it shortly goes slightly below R if I'm not moving. I did a full flush with my 60k including a backflush of the heater core. Before doing that, my car would get up to the N. It has never done it again after the maintenance and the flushing.