Overheating series 3
Junior Member
Joined: Apr 2009
Posts: 15
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There are three parts to this puzzle, radiator, thermostat, and fan.
I would put my money on the thermostat being stuck closed to be getting temps like that. I have seen my engine hit 100 but never 130, that was 98F weather with AC on full, idling in traffic.
Thermostat is easy to get to on these cars, the bolts that retain it unfortunately are not easy to get out. They have been known to strip and snap, so be prepared.
Secondly, I would recommend flushing out the radiator/engine block to get all sludge out. Sludge will increase temps.
Fan, verify that the thermal clutch works by trying to rotate the fan by hand, it should spin maybe 1/2 turn.
A good cooling system will keep the engine to 82C +- a couple of degrees in any weather. If you are having issues with the cooling system, it is best to really give it a good going over, flushing it all out and popping a new thermostat in, refilling it with nice clean fluid.
I would put my money on the thermostat being stuck closed to be getting temps like that. I have seen my engine hit 100 but never 130, that was 98F weather with AC on full, idling in traffic.
Thermostat is easy to get to on these cars, the bolts that retain it unfortunately are not easy to get out. They have been known to strip and snap, so be prepared.
Secondly, I would recommend flushing out the radiator/engine block to get all sludge out. Sludge will increase temps.
Fan, verify that the thermal clutch works by trying to rotate the fan by hand, it should spin maybe 1/2 turn.
A good cooling system will keep the engine to 82C +- a couple of degrees in any weather. If you are having issues with the cooling system, it is best to really give it a good going over, flushing it all out and popping a new thermostat in, refilling it with nice clean fluid.
Guest
Posts: n/a
Same Issue
I've got the same issue with my '83. I just received a new radiator today and hopefully will have it installed over the next week or so.
This car has had this problem since I purchased it two years ago, so I haven't been driving long distances in the car.
To let you know the process I went through to get to the radiator being the problem (or one of the problems), I looked at it this way.
1) Obviously, does the car maintain it's temp within a reasonable range? In my case no, it continued to rise the longer I drove the car. Now it did maintain temp somewhat well at idle, but that doesn't get you anywhere.
2) Is the thermostat operating correctly? On mine, I determined that it wasn't. I pulled it out and boiled it on the stove and it didn't open, so I replaced it. Not a difficult project.
3) Is the radiator clogged? Run the car untill it gets warm (or Hot) and manually feel the radiator hose to see it it is warm (careful, it can be very hot!), then check the radiator. Put your hand against the radiator in various places (with the car NOT running) and see if the radiator is warm (or hot). Check in various places to see if you find any cold spots, if you do, you've got a clogged radiator. Time to replace it ($175.00) or have yours rodded out (not recommended if you are going to keep the car).
My fan has always worked well, so I didn't even consider that it might be the problem. Dave2 has some good recommendations as far as flushing the system out thouroghly and refilling with clean coolant. I suppose the easiest way to do that is to install a flush kit (nozzle that you can hook a garden hose to) into the heater line (or where it is recommended on the kit). From my experience years ago as a Jag mechanic, I seem to remember that these cars do have some cooling issues. But if you keep the system clean and maintained they work well. If you don't, you end up with these kind of problems (stuck thermostats, clogged radiators, etc.)
I'll let you know how the new radiator does for me.
This car has had this problem since I purchased it two years ago, so I haven't been driving long distances in the car.
To let you know the process I went through to get to the radiator being the problem (or one of the problems), I looked at it this way.
1) Obviously, does the car maintain it's temp within a reasonable range? In my case no, it continued to rise the longer I drove the car. Now it did maintain temp somewhat well at idle, but that doesn't get you anywhere.
2) Is the thermostat operating correctly? On mine, I determined that it wasn't. I pulled it out and boiled it on the stove and it didn't open, so I replaced it. Not a difficult project.
3) Is the radiator clogged? Run the car untill it gets warm (or Hot) and manually feel the radiator hose to see it it is warm (careful, it can be very hot!), then check the radiator. Put your hand against the radiator in various places (with the car NOT running) and see if the radiator is warm (or hot). Check in various places to see if you find any cold spots, if you do, you've got a clogged radiator. Time to replace it ($175.00) or have yours rodded out (not recommended if you are going to keep the car).
My fan has always worked well, so I didn't even consider that it might be the problem. Dave2 has some good recommendations as far as flushing the system out thouroghly and refilling with clean coolant. I suppose the easiest way to do that is to install a flush kit (nozzle that you can hook a garden hose to) into the heater line (or where it is recommended on the kit). From my experience years ago as a Jag mechanic, I seem to remember that these cars do have some cooling issues. But if you keep the system clean and maintained they work well. If you don't, you end up with these kind of problems (stuck thermostats, clogged radiators, etc.)
I'll let you know how the new radiator does for me.
Joined: Mar 2008
Posts: 2,521
Likes: 71
From: Powell, Ohio U.S.A. 43065
That's a whole bunch of excellent advice, with one point to add:
The auxilliary cooling fan on the original poster's car should also be running, and on early 1982 there are two of them. Normally they will not kick on unless there is a pre-existing cooling system fault that is allowing the temp to exceed normal limits: so it's not the cause of his overheating, but is another problem to sort out if it hasn't been coming on at 100 C. It will be needed when running the car with A/C on in the desert heat, that's what it's on the car for.
The auxilliary cooling fan on the original poster's car should also be running, and on early 1982 there are two of them. Normally they will not kick on unless there is a pre-existing cooling system fault that is allowing the temp to exceed normal limits: so it's not the cause of his overheating, but is another problem to sort out if it hasn't been coming on at 100 C. It will be needed when running the car with A/C on in the desert heat, that's what it's on the car for.
Senior Member
Joined: Jan 2008
Posts: 216
Likes: 9
From: Just outside of Little Rock, Arkansas
Also, Barrs leak was used regularly and recommended by Jaguar, so you may have a ton of it in the radiator. If your going to take the radiator out anyway, let a radiator shop check it out, or reinstall a new one, as suggested, certainly can't hurt, and, you'll probably have to anyway sometime in the future.
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