Thermostat Problem

[PAcowboy]

     I have the '88 258 6 in my Wagon with (supposed) air. In the 6 years I've had the car I've never had the time to see if the air worked and don't know to nuch about it. I really don't like air much, only using it in my wife's car to cool off then shut it off. Every winter the heater will boil your eye's out you can drive with the window open most days.

     Back to the problem - - my thermostat only lasts 1 year. All winter the gauge only reads a little under the green. As soon as it get's into the the 50's (outside temp) the gauge spikes into the middle of the green, leaving me driving with the windsheild defroster on most summer days, blowing it out the passenger window. I know a thermostat should last more than a season, right?

     My brother says it sounds like the thermostat is only opening half way causing the spike on the gauge and the engine seems very HOT!!! After the car runs about half an hour the rad recovery container is half empty and it stays that way so I'm always adding anti-freeze each morning.

Any suggestions will help.  It's a pain chabing it every year about this time.

Steve

[mudkicker715]

I would check for a head gasket problem.

[Mernsy]

I had to drill a tiny hole in the thermostat to allow air to escape when I was filling with coolant. When I installed the 'stat I put the hole at the 12 o'clock position.
I guess what I'm saying is, "Are you sure you had it full in the first place?"

[BenM]

It's not installed backward, is it?

What temperature thermostat do you run?

[PAcowboy]

     I've been putting thermostats in for 52 yrs. Of couse, it is in right. Of course, it's filled up. I mean every year it's the same problem and I've had the car for six (6) yrs. An air bubble will travel throughout the engine until it gets to the top of the rad. It's bled off through the overflow tube and through the overthrow tank. But, it doesn't displace half a qt. of water, right?

     Also, it's not a head gasket problem.  After I change the stat it runs all year until next yr. without any problems then, I have to change it again. No leaks anywhere.

     Am perplexed!

Ateve

[doneagle]

            HI    sounds like you have a good one going there ...What size is the stats 160.....180.....200....what size are you putting in .....and have you taken the old one and put it in a pan of water on the stove to see if it opens all or half way or not at all ...that is how I check them and the right temp makes a lot of deference in how long it last .....don 

[IowaEagle]

Was the water pump replaced before you got the car?   I am thinking it may be a reverse rotation pump, probably not the issue, but I am as perplexed as you.

[PAcowboy]

I changed the pump 3 yrs. ago.

[Billman]

I would go after a plugged radiator. I had a wagon that would run a little warm until I hit 45mph then jump right to the top. Sounds kinda like the outside air temp is helping to keep it cool enough but once it gets a little warm your car is not getting enough flow to stay in a proper operating zone.

[carnuck]

Try loosening the coolant temp sensor on the head to burp the motor. A 1/16" hole in the top part of the thermostat face will bleed off the air that gets trapped otherwise.

[vangremlin]

     I have the '88 258 6 in my Wagon with (supposed) air. In the 6 years I've had the car I've never had the time to see if the air worked and don't know to nuch about it. I really don't like air much, only using it in my wife's car to cool off then shut it off. Every winter the heater will boil your eye's out you can drive with the window open most days.

     Back to the problem - - my thermostat only lasts 1 year. All winter the gauge only reads a little under the green. As soon as it get's into the the 50's (outside temp) the gauge spikes into the middle of the green, leaving me driving with the windsheild defroster on most summer days, blowing it out the passenger window. I know a thermostat should last more than a season, right?

     My brother says it sounds like the thermostat is only opening half way causing the spike on the gauge and the engine seems very HOT!!! After the car runs about half an hour the rad recovery container is half empty and it stays that way so I'm always adding anti-freeze each morning.

Any suggestions will help.  It's a pain chabing it every year about this time.

Steve

Let me make sure I understand the problem.  Because of these issues, you change the thermostat every year about this time.  The new thermostat works fine, and the car doesn't overheat during the summer.  The following winter it produces plenty of heat, but stays low in the operating range.  Then in the springtime, it starts to overheat again, and you need to change the thermostat again.  is that what's going on?  Thanks.

[BenM]

Do you use the same brand of thermostat every time?

What coolant do you use? Green, OAT, Dex-Cool compatible, all-makes?

Have you performed triage on a used thermostat to verify it's opening temperature?

Have you tried the Microsoft approach: remove the thermostat and put it back in?

This is the kind of thing that might require a strategy. If you pull the old thermostat out and it tests good AND reinstalling it solves your problem then you can eliminate the thermostat. If it tests bad, and you knew it tested good before going in you can try a different brand if you haven't.

I also would recommend getting a second temperature gauge hooked up and verifying temperatures.

If you don't turn on the defroster, does the needle reach the top of the green? An Eagle with a proper cap, pump, and coolant mix with an accurate gauge will not boil over until the needle reaches the "H". That's around 250°-265°. I average around 195° in the winter and 220° in the summer in traffic, or in the bottom 1/4 of the green in the winter and about half way up the green in the summer.

The temperature at the back of the head where the stock sending unit is attached generally reads warmer than water at the outlet.

[IowaEagle]

I am curious how a new thermostat cures this, but for only a year?  I know there are bad thermostats out there but year after year?  Check the front intake manifold hose -- it pinches if it is just plain heater hose.  I had the same problem and got the molder hose for it (also used on fords) and that solved that problem.