View Full Version : Strange overheating problem for my 88 Classic.

06-02-2007, 09:20 PM
When I turn the key on the temp gauge automatically goes to the middle before the engine even goes on. Once the engine runs a few minutes it goes to red and then goes back to the middle once the thermostat opens (I am guessing). Just yesterday it never went back to the middle after running for a few minutes and then the temp warning light came on.

Today I removed the thermostat and ran it around the block a few times. The temp gauge never moved from the middle but the temp warning light came on again after about 15 minutes. The radiator hose running from the top of the radiator to the the engine was hot and full of pressure (is this normal?). I remove the overflow cap and the pressure released. Could the temp be fine and I have a faulty temp warning light? Any ideas?

06-04-2007, 04:08 PM
When you say the top hose was hot & full of pressure do you mean it was distended, or swollen & there was a lot of pressure in the cap?

If so this may be what happened to my '88, a piston slipped liner & the engine would pressurize the cooling system, but I never had coolant loose or over heating.

Check the temp of the AF with a thermometer, to be sure it isn't just a def sender, gauge or voltage stabilizer, although the stabilizer would also effect the fuel gauge I believe.

Keep us posted.

p.s. my cure was a new engine..

06-04-2007, 09:13 PM
I had a 93 LWB 4.2 with cylinder wall sleeves slipping, I noticed that after running the car for a while and than letting it cool off completely I could open the AF fill cap and gas would escape out of the tank. This was combustion gas forced into the coolant through the cylinder sleeves.

I hope that helps!

06-05-2007, 11:54 PM
if the temp guage jumps to the middle before running i would have to say it's your temp sending unit..
did you replace the thremostat before the pressurizing took place or after?
3.5 liter or 3.9?
the slipped sleeve syndrome is more likely to happen with the 3.9l and the 4.2 l
3.5 liters or more likely to blow a gasket.
these engines do not tolerate alot of heat and will slip a sleeve or crack the block ,causing combustion to be forced back thru the coolant side of the engine,causing the pressurizing.smell your coolant ,smells funky?
hope this helps.:thumb-up:
www.singingcamel.com (http://www.singingcamel.com)

06-10-2007, 08:17 PM
Sorry I took so long to respond but I was on vacation for a week (not driving the rover). It is a 1988 Rover Classic which should mean it has a 3.5 engine in it unless someone swapped it before I purchased the car 11 years ago. I am an engine novice and have been replacing small things on the rover over the years for fun as they break.

Let me clarify my "pressure" statement. I have never felt the top hose until the temp light came on a couple of weeks ago for the first time. I opened the hood and squeezed it. It was hot but not boiling and
I could squeeze the hose sides together without a lot of effort but you could feel some (normal?) pressure in it versus how it feels when the engine is cold. I opend up the cap on the overflow reservoir when the temp light was on with a rag and there was a split second "woosh" sound which did not seem out of the ordinary.

The temp gauge always goes straight to middle as soon as I turn the key halfway before the engine starts. Once I turn the engine on the old thermostat seems to cause the gauge to go to red and does not come back down once the engine gets to running temp. Without the thermostat the gauge does not move from the middle. With or without the thermostat the temp light goes on in about 10-15 minutes.

Since I have owned the car I have always smelled a little coolant but not constantly. The head gasket was done on the car about 5 years ago (25k miles back) and the smell never went away. There is no coolant in the oil and I have never found any leaks under the car or on the floorboard. I always seem to be topping off the overflow every month or so but can never figure out where it is going. The car has always ran like a champ with no issues but is slowly starting to show its age with the usual rusting caused by living in New Hampshoire.

Is the temp light sensor located in the thermostat housing? I see two wires attached to some type of electronic sensor screwed into the housing. Thanks for all of the suggestions!!