Ok so where should the temp gauge be on an 85 GL? Mine is going up a bit past half but no further, is this ok?

And also, this weekend i flushed and replaced the coolant and found that the radiator petcock valve is on the side of the radiator, half way up. What the freak? Why do they do that, it probably only drained half the radiator. Is there another drain valve on the bottom of the radiator that I didnt see?? Let me know please, thanks....

The "normal" place for any temp guage to read should be midscale. What you want is that whatever is normal for your sender/gauge that it stays there and doesn't go higher under load.

 

Yes, you have found the one and only drain for the radiator. Makes a lot of sense, doesn't it?

Man that is nuts, what where they thinking??? I cant imagine how much junk is at the bottom of these radiators. Not cool. Oh well.

You're right it's not cool. However, if you want to drain the bottem half just disconnect the lower hose. Or if you really want to clean it, take the radiator out completely....only takes about ten minutes to remove the radiator.

 

Northwet is correct in his response to the reading on the gauge. My test is to take it on the highway and run the car up to the speed limit and look for a hill at that speed. Temp gauge should not climb above that same reading no matter what the load.

Above half is too warm. It should be at half or slightly below. Wish they were more exact

You're right it's not cool. However, if you want to drain the bottem half just disconnect the lower hose. Or if you really want to clean it, take the radiator out completely....only takes about ten minutes to remove the radiator.

 

Northwet is correct in his response to the reading on the gauge. My test is to take it on the highway and run the car up to the speed limit and look for a hill at that speed. Temp gauge should not climb above that same reading no matter what the load.

 

Overheating is a big issue on these cars. And so are the oil leaks!

 

Best bet to control temp is to swap out the thermostat with an OEM thermostat. They keep the car running *as cool as possible*.

You're right it's not cool. However, if you want to drain the bottem half just disconnect the lower hose. Or if you really want to clean it, take the radiator out completely....only takes about ten minutes to remove the radiator...

Disconnecting the lower hose will help get old fluid out, but not particulates/sludge that is on the inlet side of the radiator. Edrach's suggestion to pull the radiator is the best method to get that stuff out; might also "backflush" the radiator shile it is out and standing on end.

 

Also, please note that about half of your old coolant will still be sitting in the engine even after you pull the radiator.

Well what I did is i filled it with water a couple of times and let the engine run and then flushed it out so it recirculated the water and coolant and hopefully got most of the old stuff out of the engine.

Do temperature sensors get lazy as time goes on?

 

I've watched mine, over the years, slowly not go as high as it used to.

 

Now it barely clears the bottom line.

Hm could be your thermostat going lazy and needs replacing. Or something clogged in your coolant system thats not letting coolant go thru..

You could check the water temperature using a themometer with the radiator cap removed to see how close readings are, as the car warms up from a cold start.

You could check the water temperature using a themometer with the radiator cap removed to see how close readings are, as the car warms up from a cold start.

The problem with that is that the temp sender is on the "hottest" side of the system, and the radiator cap is on the coldest side. Could be a rather large difference.

Hm could be your thermostat going lazy and needs replacing. Or something clogged in your coolant system thats not letting coolant go thru..

 

I should point out that the fan kicks in when the temp guage is at its highest point, even though for me that is well below the middle spot.

Disconnecting the lower hose will help get old fluid out, but not particulates/sludge that is on the inlet side of the radiator. Edrach's suggestion to pull the radiator is the best method to get that stuff out; might also "backflush" the radiator shile it is out and standing on end.

 

Also, please note that about half of your old coolant will still be sitting in the engine even after you pull the radiator.

 

I agree with removing the radiator and backflushing. I do it every time I replace timing belts. I also remove the pipe plugs on the bottom of both heads to drain almost all of the coolant out of the engine block.

Easy fix... install an aftermarket temp gauge.. when i have a 180 tstat in.. it never gets above 195 or so and thats going up some serious hills with roughly 1000-1500 pounds of crap in the back.