1992 running warmer than I expected
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Good for the OP for sticking with proper maintenance and fixing the problem! 
Guys, it's not normal. 220-205 on the highway on a 70* day? No! That is NOT normal, or "O.K.". And unless the OP is driving in stop lights for 2 miles after he gets off the highway, it shouldn't heat up to 220*, that fast either. That's not right.
It is these kinds of situations (poor maintenance) that are precisely why people say things like "these cars run hot", or "C4's have marginal cooling systems", etc. They don't. The cooling system is better than good enough and the OP, with a little PM has proven that here. I've proven it too on these forums. My '92 runs at ~185-195 on 100*+ days (highway).
Again, nice job on doing a sound repair with maintenance. Pulling the knock sensors is a critical step. Do it.
Careful with the "a few years" idea. That is how you got into marginal cooling system performance in the first place. You need to make a choice; either maintain the cooling system annually...or use an extended life coolant -in which case you CAN safely "not have to worry about it for a few years".
It is these kinds of situations (poor maintenance) that are precisely why people say things like "these cars run hot", or "C4's have marginal cooling systems", etc. They don't. The cooling system is better than good enough and the OP, with a little PM has proven that here. I've proven it too on these forums. My '92 runs at ~185-195 on 100*+ days (highway).
I will plan on taking out the knock sensors and giving it one more flush before draining and refilling everything but hopefully this will resolve the issue.....
Further update:
I added some of the Prestone flush stuff and have been driving it for about 2 hours and the temperatures are a lot better, from what I have read they are close to normal. I will drain it this week and put in antifreeze and hopefully not have to worry about it for a few years.
Further update:
I added some of the Prestone flush stuff and have been driving it for about 2 hours and the temperatures are a lot better, from what I have read they are close to normal. I will drain it this week and put in antifreeze and hopefully not have to worry about it for a few years.
Careful with the "a few years" idea. That is how you got into marginal cooling system performance in the first place. You need to make a choice; either maintain the cooling system annually...or use an extended life coolant -in which case you CAN safely "not have to worry about it for a few years".
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Here is a 104*F day,
*I was driving ~70-75 mph
*I had the AC going so there is some added heat loading to the cooling system.
These cars shouldn't be running 200+ on a 70* day on the highway.
.
*I was driving ~70-75 mph
*I had the AC going so there is some added heat loading to the cooling system.
These cars shouldn't be running 200+ on a 70* day on the highway.
.
Last edited by Tom400CFI; Oct 16, 2017 at 04:04 PM.
Thread Starter
Burning Brakes
Joined: Apr 2017
Posts: 877
Likes: 80
From: Frederick MD
I pulled the knock sensors and flushed everything today. Nothing bad looking came out of the block. Filled it with coolant and took it for a drive and it does not seem like too much of a change from before (which is what I expected), still running about 197°F going down the highway.
Thread Starter
Burning Brakes
Joined: Apr 2017
Posts: 877
Likes: 80
From: Frederick MD
FYI, once I got it flushed and the antifreeze mix in, the best way I found to get that last bit of air out was to open the radiator cap and use my jelqing skills (don't google that at work) on the lower radiator hose to coax out the last bit of air.
