Automotive Forums

I have an 1988 Honda Accord sedan (automatic) that i got from a friend about a month ago.  I recently patched up the radiator with some J-B weld stuff and it no longer leaks.  But, I have noticed that it does get quite hot sometimes (mainly when it's being driven).  Since the repair work, I haven't had it actually overheat, but it the temp gauge gets very close to the red line.  Now, I did use some pure antifreeze and maybe not enough water... is that most likely the problem, or is the guage maybe bad?

I noticed that when I let the card idle for about 5-10 minutes, the temp gauge never went more than half way (so it stayed at normal temperatures), but when I started driving it, it got hotter and hotter to the point where I shut off the engine to prevent damage or overheating.  

There are 2 cooling fans in this car: one for the radiator and one for the AC.   The AC fan doesn't always work (because the AC compress doesn't turn on, which one could figure because it's an 88).  But the other fans works fine and turns on when the car is running.  Is my problem with it almost over heating most likely related to an improper mix of coolant/water?  Because I read that if you do a 70/30 mix, you get slightly higher boil over temperatures.  I live in Northern Illinois so we see some pretty cold winters and pretty hot summers.  Should I drain the radiator and start fresh with a 50/50 mix???  

I forgot to mention that before I did the repair with JB Weld, I was driving the car and the car did overheat and steam did come out of the engine.  But I ran the car after that (After putting more coolant in it) and it worked fine.  But that coolant leaked out over time as it was parked for a week.  So, I ended up adding pure coolant (because I didn't realize it wasn't a 50/50 mix until after I bought it & opened it).  I think I maybe put in about 1.5 gallons of coolant, and maybe 1 gallon of water to fill up the radiator after the repair job.  Is that maybe too much coolant and not enough water?

But the engine runs fine now, so I don't think anything got damaged too much from the overheating.  So, the cooling system does seem to work properly.  I don't see any leaks, and no indicator lights come on during operation, and the car seems to drive and idle fine... it just runs hot after about 5 minutes of driving.  

Also, I did add some Bar's Leak stop to the radiator (following the directions).  If my memory serves me right, this stuff may make the temp gauge read incorrectly for a while.  Is this true with this product?

I carefully checked the radiator when it was running hot, and it didn't feel overly hot or anything.  Is this problem maybe just that the leak stop stuff screwed up the thermostat or temp sensor(s)?  Is the car really overheating?  I would like that if it the temp gauge started to redlined, anti-freeze would start pouring out the overflow or the cap or somewhere I would see some steam... but I didn't.  

The first thing I would try is a new thermostat and a new temp sensor.The anti-freeze mixture would not make it overheat.Thay do recomend a 50/50 mixture,I like the better 70/30, boiling point is 276.  

I agree. Replace your thermostat. It could be stuck shut which wouldn't allow your engine to send its hot coolant to the radiator to be cooled. Also consider flushing the radiator if this hasn't been done lately. If your problem continues you may have a faulty gauge.