overheating problem?

Topic: overheating problem? (Read 2308 times) previous topic - next topic

overheating problem?

October 18, 2009, 05:21:26 PM

ok my needle borders the red line... after normal warm up. i just bought this car and i figured what the hell so i replace 1st thermostat. no change. looked in radiator saw corossion inside. 2nd radiator. no change figured whats left. 3rd water pump.. no change i even replaced the cap and ect sending unit by the distributor. i am at a loss. i dont believe i am air bound however i have already been wrong so i am up for any suggestions... but i did suck the system into a vacspooge and it did not change anything . now i know this sounds wierd but when i turn the heat on it seems to raise the needle higher..

overheating problem?

Reply #1 – October 18, 2009, 07:24:09 PM

Your profile says "1988 xr7", so I'm assuming the 5.0 V8?

Could be a bad sensor, a bad gauge, incorrect voltage to the gauge, or actually overheating.

If you have a volt/ohm meter, you can check the resistance of the coolant sensor, to see if it's in range. It's as good a place as any to start (And this might be better in the "Engine Tech" section).

Here's a little chart I have:

overheating problem?

Reply #2 – October 18, 2009, 09:07:13 PM

Does the engine actually feel much hotter than it should?

What's the condition of the coolant itself? New? reuse the old stuff?

How about the water pump? did you get the right one for the year of engine?
sometimes it's possible to have a non-reverse rotation w/p on a 5.0 that requires reverse rotation...

overheating problem?

Reply #3 – October 18, 2009, 11:12:36 PM

ziggycougar: thanks for the post...

overheating problem?

Reply #4 – October 19, 2009, 07:02:41 AM

coolant is fresh. new water punmp.. it is the right one. it is the 5.0. now no the car does NOT actually feel like its overheating.

overheating problem?

Reply #5 – October 19, 2009, 08:08:39 PM

get a mechanical temp guage to verify if it is running hot.
they are about 8 bucks at walmart.

overheating problem?

Reply #6 – October 20, 2009, 10:05:42 AM

I had that problem years ago on my 85 Cougar 3.8. It turned out to be the instrument panel voltage regulator. Apparently the regulator only powers that gage.

overheating problem?

Reply #7 – October 20, 2009, 07:46:08 PM

Is that in the red at idle or at cruising? If at idle I would be concerned about the fan.

overheating problem?

Reply #8 – October 20, 2009, 10:59:42 PM

NEVER believe the gauges in these cars, they lie more often than a politician...

overheating problem?

Reply #9 – October 20, 2009, 11:19:45 PM

Quote from: TurboCoupe50;295702

NEVER believe the gauges in these cars, they lie more often than a politician...

today,, thats impossible.

thanks for the help

Reply #10 – October 21, 2009, 12:06:12 AM

mechanical gauge is next to do...drove the car today to work. about 7 mins.. im in pa and its a bit chilly so take that into consideration. when i got to work i popped open the hood felt the hoses everything was warm. felt good. the needle was clearly in the red zone.. question if i was truly overheating would i not have serious signs of headgasket issues.... smoke.. car running like shiznit... something right?

overheating problem?

Reply #11 – October 21, 2009, 12:19:44 AM

I have the same problem in my 1988 thunderbird, it has a 1987 thunderbird 5.0 motor, and under normal driving it borders in the red zone. I left it running for over an hour while it was there and it never overheated, and the engine did not seem any hotter than it should.

Weather conditions don't seem to affect it, but if I let the car sit a week and do it, it usually doesn't do it for a while. At least for me, I'm thinking its something mechanical.

Does the Voltage regulator affect the gas gauge? Mine is screwey. It takes like 8-9 gallons for it to appear on the gauge.

Sorry to hijack, I just have the same problem so I thought I might be able to help/rule things out.

overheating problem?

Reply #12 – October 21, 2009, 12:53:36 AM

I have seen my car get up to operating temperature at 1/3 up the gauge. Then later I look and it's up near the top end of the "norm" range. Looking at the values at the eec's connector, the one in the heater tube on top of the intake, the temperature is the same under both cirspoogestances. I know that once my water/oil/gas gauges go up once, even if they don't max out, they will never set back down to the initial position before the voltage regulator acted up. Shutting the car off and then turning is back on seems to make the gauge sit in its appropriate place again. The gauges are worthless for anything but speed as the speedometer is typically the most accurate, as long as the correct speedo gear is installed. Oil reads on the low end although a mechanical gauge shows 60psi, coolant is just a dummy light in usefulness and from reading this thread, not even that, the tach is off by like 1,000 rpm's on some people's card, the ammeter is useful in no way, and the gas tells you when you're low but not accurate to the markings on the gauge. My speedo is off right now by like 0.5mph at 60mph - 1% is pretty good. It doesn't appear to be as correct at 20-30mph or higher than 70mph though.

If it isn't using coolant, the coolant looks fine, the upper radiator hose gets hot, the heatercore blows hot, etc, I doubt there is an overheating issue. The radiator must be hot at the same time though - cold radiator with hot hose = bad radiator. Mine is scorching top to bottom and works great with my 195 degree thermostat.

Edit:
Oh, and this is with a new gauge coolant sensor. I purchased NOS Motorcraft air charge and both coolant sensors when putting the new motor in and the gauge issues did not go away. My "low oil pressure" gauge followed me from the old motor to the new one with a different (lower mileage - not new) sensor for that too. The gauge cluster itself is just poorly designed for longevity.

update!!!!

Reply #13 – October 28, 2009, 07:34:54 AM

well good news and bad news and more good news! 1. my car is NOT overheating. 2. i just dumped a whole bunch of money on an overheating issue.when it wasnot. 3. i at least know all of those things are in great working order. 4. NOW MY TEMP AND OIL PRESSURE AND MY FUEL GAUGES ARE ALL ACTING F**KED UP... I GUESS AFTERMARKET GAUGES ARE IN ORDER OR IS THIS CLUSTER FIXABLE?

overheating problem?

Reply #14 – October 28, 2009, 07:16:12 PM

i was under the impression the instrument cluster voltage regulator could affect any or all of the guages when its failing?