Overheating
Thread Starter
Instructor
Joined: Oct 2007
Posts: 188
Likes: 3
Overheating
I have a stock 1987. It runs well for a while (10-30 miles) and then overheats. It pushes hot coolant out of the radiator into the overflow tank, over filling it and then dumps all or most of the coolant. It has a new radiator cap, a new thermostat. I replaced the belt, and the bearings in the water pump seem good. I does not have any system leaks. What is causing this?
I thought - air in the system?
I also thought - belt is on backwards and pump is running backwards - New belt - It is on correctly. I thought weak rad cap - new cap, I thought - bad thermostat, but the old one looks good and the new one does not change the problem. I thought - plugged outlet - Not checked, Collapsed hose - Maybe, but not obviously happening. What else could this be? Bad water pump?
I thought - air in the system?
I also thought - belt is on backwards and pump is running backwards - New belt - It is on correctly. I thought weak rad cap - new cap, I thought - bad thermostat, but the old one looks good and the new one does not change the problem. I thought - plugged outlet - Not checked, Collapsed hose - Maybe, but not obviously happening. What else could this be? Bad water pump?
Drifting
Joined: Nov 2005
Posts: 1,324
Likes: 5
From: Charlotte NC
Thermostats have been known (personally) to be bad out of the box. You can test it with a pot of water. Bring it to yemp with the stat in there and watch for it to open.
When your car is warming, do both upper and lower hoses pressurize?
Also, usual question, are you getting any codes? Could be a sensor gone?
When your car is warming, do both upper and lower hoses pressurize?
Also, usual question, are you getting any codes? Could be a sensor gone?
Drifting
Joined: Apr 2007
Posts: 1,339
Likes: 2
From: port charlotte fl
Pull the t-stat and make sure it's OK.Have you checked to see if the fan comes on? A freebee well worth doing is to pull the rad,clean out all the junk between it and the condensor,there will probably be lots,and wash out all the cooling channels.If none of this helps the worst case scenario maybe a head gasket leak pressurising the system.
Racer
Joined: Sep 2007
Posts: 393
Likes: 0
From: Bartonville Illinois
Head gaskets can leak to the water jackets and push hot gasses to the coolant. It can take a while for this to overheat the motor or sometimes it will just make it run hotter and never overheat. These leaks usually happen at a head bolt that goes into the water jacket.
I had a Monte Carlo that did this, I bought a fan that had more blades on it, installed a spacer to move fan closer to radiator, removed radiator and had it cleaned at a radiator shop and even installed a transmission oil cooler to remove that heat from the system. After all that failed to cure the problem, I found the head gasket leak.
I hope your problem is simpler.
I had a Monte Carlo that did this, I bought a fan that had more blades on it, installed a spacer to move fan closer to radiator, removed radiator and had it cleaned at a radiator shop and even installed a transmission oil cooler to remove that heat from the system. After all that failed to cure the problem, I found the head gasket leak.
I hope your problem is simpler.
Thread Starter
Instructor
Joined: Oct 2007
Posts: 188
Likes: 3
Solved
I "burped" the system and now it does not seem to overheat
It is on 100% water at the moment. I will drive it for a day and make sure, then dump the water, put in antifreeze and call it done. For now - air
Thanks all
I think it helped me to get into the problem
It is on 100% water at the moment. I will drive it for a day and make sure, then dump the water, put in antifreeze and call it done. For now - air
Thanks all
I think it helped me to get into the problem
Thread Starter
Instructor
Joined: Oct 2007
Posts: 188
Likes: 3
Thermoidel and stopp
Well it ran trouble free for 50 miles. Then, back to overheating problems . Arggg!!! I took the thermostat out and it is running cool now.
I think I will leave it this way for a while. The temp is now not regulated well and it seems to drift between 100 - 215. 160-190 seems normal. It also appears stopped at idle is the hotest
I think I will leave it this way for a while. The temp is now not regulated well and it seems to drift between 100 - 215. 160-190 seems normal. It also appears stopped at idle is the hotest
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6th Gear
Joined: Jul 2008
Posts: 6
Likes: 0
86 overheating
Im having the same problem
with my 86, removed the rad. & cleaned
out that space. also checked t-stat.
If I have a head gasket leak will it blow
white smoke? how do I check the for a leak.
also I checked the top hose when it overheating
and it hard as a rock, bottom hose is not.
thanks,
Tonyjzrose
with my 86, removed the rad. & cleaned
out that space. also checked t-stat.
If I have a head gasket leak will it blow
white smoke? how do I check the for a leak.
also I checked the top hose when it overheating
and it hard as a rock, bottom hose is not.
thanks,
Tonyjzrose
Racer
Joined: Sep 2007
Posts: 393
Likes: 0
From: Bartonville Illinois
I will probably be chastised by many about this post.
If you think you may possibly have a small combustion leak to the coolant you could by a can of "Bars Leak". Water pump lube and stop leak. Put the oil in and a dozen or so of the pelets and drive it for a while.
I have used this stuff for well over 30 years with no ill effects. The pellets are "ginger" and I never put them all in.
With a direct drive water pump, I don't know how to do the test where you look for bubbles in your thermostat housing because the pump is running.
Maybe someone else can chime in.
If you think you may possibly have a small combustion leak to the coolant you could by a can of "Bars Leak". Water pump lube and stop leak. Put the oil in and a dozen or so of the pelets and drive it for a while.
I have used this stuff for well over 30 years with no ill effects. The pellets are "ginger" and I never put them all in.
With a direct drive water pump, I don't know how to do the test where you look for bubbles in your thermostat housing because the pump is running.
Maybe someone else can chime in.
Drifting
Joined: Apr 2007
Posts: 1,339
Likes: 2
From: port charlotte fl
Im having the same problem
with my 86, removed the rad. & cleaned
out that space. also checked t-stat.
If I have a head gasket leak will it blow
white smoke? how do I check the for a leak.
also I checked the top hose when it overheating
and it hard as a rock, bottom hose is not.
thanks,
Tonyjzrose
with my 86, removed the rad. & cleaned
out that space. also checked t-stat.
If I have a head gasket leak will it blow
white smoke? how do I check the for a leak.
also I checked the top hose when it overheating
and it hard as a rock, bottom hose is not.
thanks,
Tonyjzrose
6th Gear
Joined: Jul 2008
Posts: 6
Likes: 0
overheating
new WP, new t-stat, removed & cleaned out
the Rad., fans are working.
the belt is not squeaking at all,
just has alot of movement,
when A/C is running tensioner
start jumping.
Thank,
Pro
Joined: Nov 2005
Posts: 602
Likes: 0
From: North Bay Ontario
sorry to say, but if you have eliminated the t-stat as a possible problem, I'd be almost certain that you have an internal head gasket leak based on the description. Also, running straight water at temps approaching 215 could be a possibility as you have exceeded the boil point of the water, and don't have much of a margin left even with the system under pressure.
Before tearing anything down - do a pressure test and see if the system holds pressure - that will give you a clear answer. - Not a compression test, just a basis coolant system pressure test.
Before tearing anything down - do a pressure test and see if the system holds pressure - that will give you a clear answer. - Not a compression test, just a basis coolant system pressure test.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Read Vaders post! or the FSM. If you're only hitting 215...no problem, even higher is within range. Stock fans don't even come on at 215. Normally the main comes on around 228, and the aux. 232, or around there.
When I first bought my 87, almost 10 years ago it hit 240 in stop and go on a very hot day. I went with a new 180 thermostat, cleaned the area between radiator and condensor (alot of crap), bought a lower fan switch for the aux. fan and wired the main fan into it....both fans come on at 205, and shut off at 190. It has since always hit 205-207 in stop and go traffic on warm days, cools down with the fans. I can almost see the thermostat opening and closing by the temp. guage.Cruising it runs around 180 all day long.
When I first bought my 87, almost 10 years ago it hit 240 in stop and go on a very hot day. I went with a new 180 thermostat, cleaned the area between radiator and condensor (alot of crap), bought a lower fan switch for the aux. fan and wired the main fan into it....both fans come on at 205, and shut off at 190. It has since always hit 205-207 in stop and go traffic on warm days, cools down with the fans. I can almost see the thermostat opening and closing by the temp. guage.Cruising it runs around 180 all day long.
Instructor
Joined: Dec 2007
Posts: 156
Likes: 0
From: Powhatan Virginia
Multiple Burps ??
Did this problem occur after ANY repairs had been made-- if so it sounds like air as you had stated---sometimes it can take a few days and multiple "burps" to get all the air out--Are you sure you have the correct cap and that it is sealing when closed?--it is normal for these cars to run "hotter ' than most people would consider normal---if the problem occured all on it's own---I would check-- as was stated in other posts-- the area between the radiator and the AC condenser for trash/debri C-4s are known for sucking up everything they can- from off the road---Now about the headgasket--there is kit available with a sort of "dye" that goes in the cooling system which changes colors when it detects combustion/exhaust gases--it will show you whether or not you have a blown headgasket--cracked head--or cracked block---Lastly I would not advise running 100% water 'cause it boils at a much lower temp than a antifreeze/water mix--I'll say again-- normal for C-4 to run hotter BUT not so hot they push coolant out of the system.
