High Coolant Temperature
#16
Team Owner
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I am with Seans diagnosis here. and its good opportunity to replace the thermostat seals and T stat and heater control valve and short hose and coolant cap.
might not be a bad idea to replace the waterpump with a new Laso with plastic impeller.
Or carry an extra shear bushing for the guardian and all the tool to swap it on the road.
NOTE dont run the car till the waterpump has been removed and inspected,
or you could damage the HGs
might not be a bad idea to replace the waterpump with a new Laso with plastic impeller.
Or carry an extra shear bushing for the guardian and all the tool to swap it on the road.
NOTE dont run the car till the waterpump has been removed and inspected,
or you could damage the HGs
#17
Rennlist Member
Thread Starter
Join Date: Oct 2005
Location: Gatineau, Québec, Canada
Posts: 5,179
Received 1,320 Likes
on
500 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Thanks Stan.
Your advices are always very appreciated.
I'll do a pressure test and coolant test tonight.
And dig to the water pump after that and see what happened.
I have a spare Laso WP available. Thanks Luc!
Thanks again.
Your advices are always very appreciated.
I'll do a pressure test and coolant test tonight.
And dig to the water pump after that and see what happened.
I have a spare Laso WP available. Thanks Luc!
Thanks again.
Last edited by Bertrand Daoust; 06-19-2017 at 09:29 PM.
#18
Rennlist Member
Thread Starter
Join Date: Oct 2005
Location: Gatineau, Québec, Canada
Posts: 5,179
Received 1,320 Likes
on
500 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Bertrand,
You might be better served initially by trying to do a pressure test at 14 psig on the cooling system. A failed impeller will likely [but not necessarily] hold pressure whereas a head gasket should not do so.
If the impeller drive has failed somehow the engine will over heat quite quickly- I have had that happen twice when the plastic impellers came off. If your heads have never been off then a head gasket failure is distinctly possible given the 26 years of age. And indeed- the thermostat should be investigated.
Good luck whatever the problem may be.
Fred
You might be better served initially by trying to do a pressure test at 14 psig on the cooling system. A failed impeller will likely [but not necessarily] hold pressure whereas a head gasket should not do so.
If the impeller drive has failed somehow the engine will over heat quite quickly- I have had that happen twice when the plastic impellers came off. If your heads have never been off then a head gasket failure is distinctly possible given the 26 years of age. And indeed- the thermostat should be investigated.
Good luck whatever the problem may be.
Fred
It wasn't holding the pressure. Then noticed that both upper and lower hoses were leaking at the thermostat side. I tight both and it's good now.
I put back 14 psi and maybe lost 1/10 of a psi in about 15 minutes.
I think that's good. Right?
What I'll do next, is lift the car, remove the belly pan, air tube, air filter box and inspect every coolant rubber hoses, pipes, etc. with pressure applied and make sure that everything is tight enough.
I could not get some fluid today for the block tester. Might get some later this week.
Then I'll get down to the pump to look at it.
Thanks guys.
#19
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Trinity says good luck with your repairs!
#21
Addict
Rennlist Member
Rennlist Member
Join Date: Oct 2003
Location: Gone. On the Open Road
Posts: 16,511
Received 1,652 Likes
on
1,076 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
The engine indeed was very warm.
Coolant was very hight in the expansion tank.
Very close to the coolant cap.
...
Once at home and the car cooled, I noticed that the coolant level in the expansion tank was way too low. About 2 inches lower than the level mark.
No trace of coolant anywhere I can see (for now).
Coolant was very hight in the expansion tank.
Very close to the coolant cap.
...
Once at home and the car cooled, I noticed that the coolant level in the expansion tank was way too low. About 2 inches lower than the level mark.
No trace of coolant anywhere I can see (for now).
In either case you'd not, likely, find evidence of coolant: it would have vaporized if not vapor already and/or dripped onto the road while driving.
Already expressed possibilities: thermostat, guardian pump's bushing are spot on.
I think it highly unlikely that a head gasket popped. Your pressure test seems to confirm that (at least with a cold engine.) Leave the pressure on overnight, then pull the plugs and check for coolant in the cylinders. (I doubt you'll find any.) A super-clean plug unlike any of the others might, however, be a smoking gun.
#22
Addict
Rennlist Member
Rennlist Member
Join Date: Oct 2003
Location: Gone. On the Open Road
Posts: 16,511
Received 1,652 Likes
on
1,076 Posts
#23
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Bertrand,
You said that you had a temperature alarm flash up but unless I missed it, you did not mention where the temperature gauge needle was. Did it show abnormal behaviour in terms of higher indicated temperatures such as the needle moving into the red zone or clearly above where it normally sits?
You said that you had a temperature alarm flash up but unless I missed it, you did not mention where the temperature gauge needle was. Did it show abnormal behaviour in terms of higher indicated temperatures such as the needle moving into the red zone or clearly above where it normally sits?
#24
Rennlist Member
Thread Starter
Join Date: Oct 2005
Location: Gatineau, Québec, Canada
Posts: 5,179
Received 1,320 Likes
on
500 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
The needle went right to the red zone.
The warning "Overheating" was flashing in red and little red light was on.
Not fun at all!
Before that happened, the normal driving temperature was right before the last white line (90C?) with a 83 thermostat installed last year. Before that I had a 75 degree thermostat and the normal temp. was just above the first white line. I didn't like that so put a 83 degree.
Thanks.
The warning "Overheating" was flashing in red and little red light was on.
Not fun at all!
Before that happened, the normal driving temperature was right before the last white line (90C?) with a 83 thermostat installed last year. Before that I had a 75 degree thermostat and the normal temp. was just above the first white line. I didn't like that so put a 83 degree.
Thanks.
#25
Rennlist Member
Thread Starter
Join Date: Oct 2005
Location: Gatineau, Québec, Canada
Posts: 5,179
Received 1,320 Likes
on
500 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
The coolant, in liquid and vapor form, would have escaped from the vent tube of the overflow tank once the pressure in the system exceeded the relief pressure of the tank's cap. A new cap would release at no more than 14 PSI. An old cap might release at 7 PSI or less.
In either case you'd not, likely, find evidence of coolant: it would have vaporized if not vapor already and/or dripped onto the road while driving.
Already expressed possibilities: thermostat, guardian pump's bushing are spot on.
I think it highly unlikely that a head gasket popped. Your pressure test seems to confirm that (at least with a cold engine.) Leave the pressure on overnight, then pull the plugs and check for coolant in the cylinders. (I doubt you'll find any.) A super-clean plug unlike any of the others might, however, be a smoking gun.
In either case you'd not, likely, find evidence of coolant: it would have vaporized if not vapor already and/or dripped onto the road while driving.
Already expressed possibilities: thermostat, guardian pump's bushing are spot on.
I think it highly unlikely that a head gasket popped. Your pressure test seems to confirm that (at least with a cold engine.) Leave the pressure on overnight, then pull the plugs and check for coolant in the cylinders. (I doubt you'll find any.) A super-clean plug unlike any of the others might, however, be a smoking gun.
I'll check the plugs also. They're new from this year.
Thanks Dave.
BTW, nice meeting you in Chestertown!
Last edited by Bertrand Daoust; 06-20-2017 at 08:18 AM.
#26
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
The needle went right to the red zone.
The warning "Overheating" was flashing in red and little red light was on.
Not fun at all!
Before that happened, the normal driving temperature was right before the last white line (90C?) with a 83 thermostat installed last year. Before that I had a 75 degree thermostat and the normal temp. was just above the first white line. I didn't like that so put a 83 degree.
Thanks.
The warning "Overheating" was flashing in red and little red light was on.
Not fun at all!
Before that happened, the normal driving temperature was right before the last white line (90C?) with a 83 thermostat installed last year. Before that I had a 75 degree thermostat and the normal temp. was just above the first white line. I didn't like that so put a 83 degree.
Thanks.
That clearly rules out a false indication.
Your symptoms appear very much like what happened first time my water pump lost the impeller during our hot summer time. Quite possible you puked some coolant from the expansion tank as the over pressure device in the cap lifted - is the cap newish or old?
That you are holding test pressure suggests the pump is the problem- will do no harm to take a look at the thermostat though given you will need to drain off the coolant to get at the pump.
I know just about squat about that type of pump but if the coupling has sheared in the way it is designed to do as a protective measure, it will be interesting to know why it let go. First things first however and probably time to extract the pump to see if that is the root cause of the overheating.
#27
Rennlist Member
Thread Starter
Join Date: Oct 2005
Location: Gatineau, Québec, Canada
Posts: 5,179
Received 1,320 Likes
on
500 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Bertrand,
That clearly rules out a false indication.
Your symptoms appear very much like what happened first time my water pump lost the impeller during our hot summer time. Quite possible you puked some coolant from the expansion tank as the over pressure device in the cap lifted - is the cap newish or old? The cap (''100'') is one year old.
That you are holding test pressure suggests the pump is the problem- will do no harm to take a look at the thermostat though given you will need to drain off the coolant to get at the pump. Before going to the pump, I plan to drop coolant from the rad and get to the thermostat and check it first.
I know just about squat about that type of pump but if the coupling has sheared in the way it is designed to do as a protective measure, it will be interesting to know why it let go. First things first however and probably time to extract the pump to see if that is the root cause of the overheating. If the thermostat is fine, I'll get to the pump and know for sure if the coupler did let go. If it's the case, it will of course be interesting to know why.
That clearly rules out a false indication.
Your symptoms appear very much like what happened first time my water pump lost the impeller during our hot summer time. Quite possible you puked some coolant from the expansion tank as the over pressure device in the cap lifted - is the cap newish or old? The cap (''100'') is one year old.
That you are holding test pressure suggests the pump is the problem- will do no harm to take a look at the thermostat though given you will need to drain off the coolant to get at the pump. Before going to the pump, I plan to drop coolant from the rad and get to the thermostat and check it first.
I know just about squat about that type of pump but if the coupling has sheared in the way it is designed to do as a protective measure, it will be interesting to know why it let go. First things first however and probably time to extract the pump to see if that is the root cause of the overheating. If the thermostat is fine, I'll get to the pump and know for sure if the coupler did let go. If it's the case, it will of course be interesting to know why.
#28
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
You don't really need to drain any coolant to get at the t-stat.
When I bought my 79 it had t-stat issues. I jacked up the nose as high as I could, coolant loss was very minimal since the t-stat housing was now the highest point in the system.
When I bought my 79 it had t-stat issues. I jacked up the nose as high as I could, coolant loss was very minimal since the t-stat housing was now the highest point in the system.
#29
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I am going to remain very optimistic on this one. That car is too nice, too well loved to have some sort of major catastrophic failure.
#30
Rennlist Member
Join Date: Aug 2014
Location: Adirondack Mountains, New York
Posts: 2,420
Received 318 Likes
on
166 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
When it does, the symptoms are rising temperature and then a low-coolant warning. The hose doesn't entirely pop off, it just starts leaking coolant - not a lot, but enough to relieve pressure. Some or most of the missing two quarts might be from steam. Nothing visible from inside the car, surprisingly.