cold running vehicles
Thread Starter
|
Elder User
Joined: Dec 2002
Posts: 550
Likes: 1
From: Effingham,IL USA
cold running vehicles
anybody ever been stumped by a vehicle that allways runs cold? i mean not thermostat stuck open? my 91 sunbird will not run above 130-140 degrees. had 5 thermostats in it and no change. it runs the same if you take the thermostat out. by the way its got a 2.0 with the 'stat under the radiator cap, takes about 7 seconds to change. we checked it with a thermocouple probe and it wont get above 140. it has 180000 miles and has bubles in coolant when running. uses no oil or antifreeze. can a blown head gasket cause coolant undertemp? i'm stumped. the cam is also noticibly worn but it gets 30 mpg and runs good. i've blocked off the radiator completly and this doesnt even help. it has good heat until about 20 degrees, then you freeze.no check engine light on. iv'e got a thermometer in my trucks center dash heater vent and got 170 degrees the other day in the middle of winter out the dash- thats 30or 40 degrees hotter than my cars engine in the middle of summer!! anybody else have a cold car/truck?
Posting Guru
Joined: Sep 2002
Posts: 1,154
Likes: 0
cold running vehicles
Well, if you had a blown head gasket your car would be doing the opposite it would be overheating in a matter of seconds. Also I have never heard of a thermostat under the radiator cap. How does that work?
Thread Starter
|
Elder User
Joined: Dec 2002
Posts: 550
Likes: 1
From: Effingham,IL USA
cold running vehicles
well the "radiator cap" isnt really on the radiator. it's on the thermostat housing bolted to the engine. the thermostat has a handle on it. you just take the cap off, and pull out the therm. kinda wierd setup, but the easiest to change!. you are completly wrong on blown head gaskets causing vehicles to instantly overheat. you can run an engine with a blown head gasket. it is more prone to sudden overheating, but it can run a long, long time. i've had 2 cars with blown head gaskets and drove them thousands of miles. my old 87 tbird would use about half a gallon of water on my 80 mile roundtrip to college every day. it did suddenly overheat more than once. but i drove it thousands of miles with normal coolant temps. when it would overheat i would have to stop and open the hood and let it cool for about 15 minutes, then it was good. my nephew has the same problem on his cougar. 3.8 ford motors are real bad in that concern. they all blow their head gaskets.
Post Fiend
Joined: Feb 2000
Posts: 11,496
Likes: 6
From: Kansas
cold running vehicles
Have you pressure checked the system? If it can't pressurize, then it will have a harder time reaching or maintaining the temp you want.
The bubbles in the coolant are the key IMHO.
The bubbles in the coolant are the key IMHO.
Posting Guru
Joined: Dec 2002
Posts: 1,297
Likes: 3
From: Billings MT
cold running vehicles
As said before, the bubbles are probably the key. It sounds like it is either getting air or is getting too turbulant.
If you take your thermo out, the system has no restriction. The thermo closes and keeps water in the radiator to cool and then releases into block, its a cycling action from what I was told.
One more thing, your car should have an electric fan. Does the fan always run? If it does, there's your problem. The fan is controlled by a thermocouple and should only run once the antifreeze reaches 190*. I had a 91 grand am with a 92 2l 4 banger. When I bought the car, the electric fan was unplugged. It overheated in 6 miles. The switch was bad or something (horrible replacement job on the motor), so I wired it direct, figured better than overheating. The motor never got warm. The water was back cycling or something, but it never got above 120* I would say.
Just a few suggestions.
If you take your thermo out, the system has no restriction. The thermo closes and keeps water in the radiator to cool and then releases into block, its a cycling action from what I was told.
One more thing, your car should have an electric fan. Does the fan always run? If it does, there's your problem. The fan is controlled by a thermocouple and should only run once the antifreeze reaches 190*. I had a 91 grand am with a 92 2l 4 banger. When I bought the car, the electric fan was unplugged. It overheated in 6 miles. The switch was bad or something (horrible replacement job on the motor), so I wired it direct, figured better than overheating. The motor never got warm. The water was back cycling or something, but it never got above 120* I would say.
Just a few suggestions.
Thread Starter
|
Elder User
Joined: Dec 2002
Posts: 550
Likes: 1
From: Effingham,IL USA
cold running vehicles
ya the car has an electric fan. it almost never runs. it does work, though. i'm with you guys thinking the bubbles in the coolant is the key to runnin so cold. i've just never heard of or talked to anybody that had this problem. wierd, but then again its made by the general. it also has a horn that will go off when its real cold , like in the middle of the coldest night of the year,and wont shut up until you unplug it. it did it to me last year once, after that it got unplugged. i'm gonna replace the horn switch sometime.
Elder User
Joined: Jan 2003
Posts: 796
Likes: 1
Trending Topics
Thread Starter
|
Elder User
Joined: Dec 2002
Posts: 550
Likes: 1
From: Effingham,IL USA
cold running vehicles
i'm pretty sure it wouldnt pressurize. if combustion gases get into the coolant, then i'm sure it wouldn't hold much pressure. the kicker here is that its not using coolant. i'd much rather have a combustion leak into the coolant than a coolant leak into the cylinder. why do you think an un pressurezed system would not heat up?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Ford Super Duty: 5 Things Owners LOVE, 5 Things They LOATHE!
Joe Kucinski
Every 2026 Ford Truck Engine RANKED from WORST to FIRST!
Michael S. Palmer
The Best F-150 Deal of Every Trim Level (XL through Raptor)
Joe Kucinski
Post Fiend
Joined: Feb 2000
Posts: 11,496
Likes: 6
From: Kansas
cold running vehicles
A un pressurized system would heat up, but it will not reach the steady temp that the system was designed for since the system is "bleeding". I agree that you may have pointed us in the right direction and it may in fact be leaking exhaust gas into the system. Either way, the system is not right and may need a coolant pressure check or a cylinder pressure check.
Thread Starter
|
Elder User
Joined: Dec 2002
Posts: 550
Likes: 1
From: Effingham,IL USA
cold running vehicles
i've done compression check on the cylinders and it was ok there. i'm 99.9 percent sure that if i replace the cam, head gasket, and do a cyl head rebuild the problem will go away. i'm sure there is combustion gases getting into the coolant, you can smell gas fumes in the coolant overflow bottle and in the therm housing. but i still cant see how no pressure will not let the temp. get to 195 where it should be.
Posting Guru
Joined: Dec 2002
Posts: 1,297
Likes: 3
From: Billings MT
cold running vehicles
I'm not really sure why cooling systems never reach the operating temperature without pressure. But, if you take the radiator cap off, and run a vehicle it will never get hot.
Your thought of leaking combustion gasses into the water jacket of the block is probably right on. Whether you have an opening into the system or out of the system, it's not closed and these systems need to be closed to work right.
I have to LMAO about the horn. My '91 grand am did the same thing one morning. Completely drained the battery by the time I got out there to shut it off. Neighbors weren't too pleased. OOPS!
It's easier to heat things when they are in a closed system. A perfect example is that a pan of covered water will boil faster than a pan without a lid on it. And with that thought, an open coolant system won't reach temp as one that is closed. It's a very long theory and its been too many years since school to explain it. It's just a part of nature.
Your thought of leaking combustion gasses into the water jacket of the block is probably right on. Whether you have an opening into the system or out of the system, it's not closed and these systems need to be closed to work right.
I have to LMAO about the horn. My '91 grand am did the same thing one morning. Completely drained the battery by the time I got out there to shut it off. Neighbors weren't too pleased. OOPS!
It's easier to heat things when they are in a closed system. A perfect example is that a pan of covered water will boil faster than a pan without a lid on it. And with that thought, an open coolant system won't reach temp as one that is closed. It's a very long theory and its been too many years since school to explain it. It's just a part of nature.
Post Fiend
Joined: Feb 2000
Posts: 11,496
Likes: 6
From: Kansas
cold running vehicles
Originally posted by oldfordtrucksrule
but i still cant see how no pressure will not let the temp. get to 195 where it should be.
but i still cant see how no pressure will not let the temp. get to 195 where it should be.
Junior User
Joined: Mar 2003
Posts: 66
Likes: 0
cold running vehicles
if you havent replaced the rad. cap i would,or maybe you could get a higher pressure one for it. and on those cold days when the heater isnt cuttin it,take cardboard and cover part of your radiator,about half of it,keep an eye on temp gauge though.but if it still isnt warm cover up a lil more.and in a pinch,a floor mat works too lol.i would bout bet youll have heat then.just dont do what this one dude did,he used a cheerios box with the outer part facin out ,and the grill was busted up so it looked dorky lol
Posting Guru
Joined: Dec 2001
Posts: 1,668
Likes: 3
From: Lincoln USA
cold running vehicles
One more question: Where are you buying your thermostats? The large discounts chains do not have a very good reputation on this board for selling quality parts. Try a 'stat from NAPA, and place it in a pan of water deep enough to completely cover the 'stat. Suspend a cooking thermometer in the pan, being careful it doesn't touch the bottom, and check to see at what temperature the 'stat opens. Should be around 180-190 degrees.