92 Honda Accord EX runs hot

[eric trepid]

I have a 1992 Honda Accord EX and for some reason this car runs hot. Only takes a block or 2 of driving for the temp to get halfway. I have noticed latley that the temp shoot up if I use the air conditioning for more than 45 minutes.
Here is what I have donw:

Replaced the Water Pump
replaced all rubber hoses related to cooling
Replace the radiator
Replaced the thermostat several times - even tried different temps.
There is no water in the oil.
No smoke from the tailpipe.
Has over 160K in mileage.
The radiator fans do come on while driving and when the car is off.
It has been like this for a year and I am stumped!

[94hondaacc]

hoe bout the tempature sending unit. it could be a false reading that the car is sending to the needle. go to a shop that has a digital thermometer to figure out the true tempature of the engine. hope this helps good luck.

[eric trepid]

Actually the engine does get pretty hot. When it is raining, I can see steam come from the top of the hood. Maybe the sending unit is faulty and not sedning the right signals to the other devices? But the thermostat does this job, releasing water to the engine when needed.

[94 Accord]

If not the temp sending unit. Have you checked the timing? I heard that can effect the temp if the timing is not right.

[eric trepid]

Originally Posted by 94 Accord

If not the temp sending unit. Have you checked the timing? I heard that can effect the temp if the timing is not right.

Could be possible. I will have to check the timing but the car runs fine, no sputters.

[hondamechanic]

Eric,

A couple of other things that might be causing your woes:

1. The radiator cap may not be sealing properly. If the seal is bad, then the system cannot build the pressure necessary to keep the coolant from boiling and allow it to flow and cool properly. If you haven't done so already, pressure check the cap (should be able to take the cap to any garage/parts store and have it checked for free). As a side note, even new caps can have manufacturing defects in them.

2. The system has air trapped in it somewhere. You will notice a bleeder valve on your thermostat housing. If air got trapped in the system when you replaced all those parts and didn't get bled out, the air pocket will cause a similar pressure problem as the bad cap. Also, the air will become super-heated and will cause hot spots in your engine wherever it is trapped. This air will not only transfer its heat to the passing coolant, it will also cause the cooling system to be less effective. When the car is cold, just crack open the bleeder (while the radiator cap is off) and see if any air comes out. Make sure to add a little water to the radiator to ensure any air that is close by gets pushed toward the bleeder.

3. You may have a bad head gasket or a crack in the block/head. I understand that you aren't seeing any smoke when you rev the engine (obvious bad head gasket)... but the leak doesn't have to be just water jacket-to-combustion chamber. The split or crack could be so small that it only leaks when there is sufficient heat and pressure on it... like from the force of combustion. You could be leaking exhaust gases into the cooling passages, and THAT will cause some serious heat issues.

As far as your water temp skyrocketing when you use the AC, that is probably because you are adding heat and effort to an already overtaxed cooling system. The AC condenser (which pulls the heat away from the freon) is located in front of the radiator. When you run the AC you are causing there to be a significant heat source in front of the radiator, essentially pre-heating the air that is supposed to cool the engine off. Also, you are adding a load onto the engine, forcing it to work harder in order to run the AC in addition to everything else it needs to do. This will cause the engine to heat up more, too. Normally, on a car with a properly functioning cooling system, this isn't a problem.

So what can you do?

Try the cap thing first. If that proves to be a dead end, bleed teh cooling system. In fact, bleed it anyway. Couldn't hurt. Finally, you could try some stop-leak. There are many brands of this stuff and it comes in powder as well as liquid form. I have had various successes and failures will both types and from different manufacturers, so I cannot recommend one over another. I can tell you that it won't harm your system. If you try it and find out that it works, great. I'd flush the system after about 50 miles or so, just to get rid of any excess stop-leak, but only because I'm particular.

Don't doo all of these in the hopes of eliminating the problem. Do them one at a time so you can isolate which one (if any) fixes the problem. If you find that the stop-leak seems to have fixed the problem, then you need to decide whether or not to fix the internal problem or just let the stop-leak ride until it fails (which it will over time) and causes the same or worse.

Hope this helps.

Steve
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