HI EVERYONE,

I HAVE A 87 951 WITH 92K MILES AND IT'S ABOUT 20 DEGREES FARENHEIT WHERE I LIVE. THE PROBLEM IS THAT WHEN THE CAR IS IDLING IT STARTS TO MOVE UP TO THE 3RD HIGHEST MARK ON THE TEMP GUAGE AND MY HEAT GETS COLD, BUT IF I STEP ON THE GAS TO REV IT UP TO ABOUT 3K RPM WHILE STILL AT A STOP THE TEMP GOES DOWN UNDER HALF AND THE HEAT GETS HOT AGAIN.

I DON'T HAVE ANY WHITE SMOKE OR WATER IN THE OIL BUT SOMEWHERE THERE MUST BE A SMALL LEAK CAUSE I ADD ABOUT A QUART A MONTH OF COOLANT. I DONT SEE ANY FLUID LEAKING ANYWHERE THOUGH.

HAS ANYONE HAD THIS PROBLEM?

THANKS IN ADVANCE

 

Do you know approximately what the coolant/water ratio is?

 

Your heat cycling symptoms sound like air in the cooling system. You are already aware of a leak too.

I would recommend doing a "cold" pressure test. Buy or rent/borrow a cooling system pressure tester that connects to the coolant fill plug. If you carefully inspect the coolant lines, hopefully you can see the leak.

 

magia81, sounds to me like you have signs of a leaky headgasket. I was having this exact same problem, and it kept getting worse --> when I revved the engine, the heat would stay cold, instead of returning like it had before. I looked into the problem, and realized that the heater wasn't working because there was air in the cooling system, and there was air in the cooling system because I had a leaky headgasket which drained the coolant reservoir causing the air to get in. I'm in the process of getting the heatgasket fixed, hope this helps.

 

In addition to the good advise from the other responses, there are three other places for leaks that usually won't show up on the ground.
The water control valve at the back of the motor above the bell housing can drip onto or into the bell housing and evaporate from there. If it goes into the bell housing on the clutch etc., bad news.
The pump that circulates coolant thru the turbo following shut down has an O ring that can leak but the water is hot and evaporates quickly. This an easy fix.
There is a short (about 2-3" hose at top front of engine under the intake tubs that can corrode and leak without making a puddle.
I would visually check these locations before I called any loss of coolant problem fixed.

 

Thanks for the tips!

Does anybody think this could be signs of a water pump going bad?

 

I blead the coolant system today and that was not the problem. I'm thinking it's either the water pump or thermostat.