Hey Guys,

As the title states, I'm dealing with my 91 Si daily driver overheating RANDOMLY. I mean random, but there has to be a cause.... OBVIOUSLY. Here are the details:

A couple of weeks ago I got off the highway hit a stoplight and the gauge started climbing. I started moving and the gauge danced a little and continued climbing. I pulled over, let it cool and grabbed a bite to eat. I started it up, put the windows down and turned off the AC. Did not have another problem until a few days later. Getting off the interstate this time and still moving it overheated. Here was my first attempt to fix:

I drained the coolant, flushed the entire system with the thermostat removed for five minutes, put PEAK flush in, ran it for two days. And I put a new thermostat that opens at 185 degrees in. Did not have another problem for three weeks or so.

Yesterday I drove the civic 250 miles all over the place highway and city with the AC on and nothing happened. Then, last night I made a quick five minute trip from the house to Kohls with the wife and on the return trip, with the windows down and the AC and fan off, it started overheating while I was going 30 miles in hour, cruising in fourth gear through a residential area....

Any ideas guys? I don't think it's the headgasket. The coolant was a little dirty, but it was not milky. Neither was the oil when I changed it last weekend. The previous owner was a mechanic and showed me papers where he changed the timing belt and water pump. Could it in fact be the water pump? Ideas and solutions are much appreciated! Everyone have a good and safe weekend!

Brian

 

Sounds like the radiator fan(the one on the passenger side). Seems like maybe it's not quite dead yet, or your a/c fan has been compensating for it. It could also be a faulty sensor.

 

check water pump also...new parts sometimes fail. keep a record of the instances when it begins to overheat to see if there is a pattern

 

Ok. I have been keeping record of the three times it has happened. Radiator fan works. The last time I was driving when it overheated. I may just go ahead and replace the water pump and see if that helps. Can I rule out head gasket if the oil and coolant are clean?

Thank you for your help.

 

Update: I have not driven the car since it overheated last week. However, I compiled my list of times that it overheated...

1) Coming off the interstate, sitting at a stoplight. I pulled over, checked the overflow bottle (full) and left the accesory on to ensure the fans were running (they were). Walked inside to eat, came back out and started it up, drove the rest of the day with no issue.

2) Came off of the interstate, but this time I was moving when it started overheating. No stoplights were hit when the needle started climbing. I threw the heat on the windshield and babied it home. Changed and flushed the fluid, put in a new thermostat.

3) Drove it all day highway and city with the ac on for work. Went home and sat it for a few hours. Went to Kohls with the lady and on the way home, in what was maybe a ten minute drive going 45 at the fastest and stopping occassionally for red light, it heated up as I was pulling in the neighborhood going 30.

So one and two saw highway speeds where maybe the motor was working harder, then when I slowed down the cooling system was unable to keep up with the heat. However, with three I was driving slow and easy.

I got an email from a fellow Richmonder. He said to replace the radiator, because the plastic tanks in these things make it impossible to really clean them. I'm going to try that. I will report back once I have the new radiator and update over time if I have another problem. The overheating had not occured for a couple of weeks between incidents, so it may take a while to do so again.

 

GL....let us know what happens