Overheating 4 cyl, Help, please look again!

[joetoken]

Please read last post, thanks


Car is 92, radiator replaced in 04, overheats at highway speeds, does not around town. I replaced water pump and thermostat, still overheats, gets about 3/4 of the way up the dial, does not peg out to H. It does better with A/C off, but still does not run where it is supposed to. I am wondering if you have to purge the air out of the system when you change water pump, I don't have a book so I don't know. Also, can anyone thinkg of another reason for overheating at highway speeds.

it looks like oil pump working, ie, if I take off oil cap when running there is some oil splatter, but only idiot light so don't know if presure is low

any suggestions would be appreciated.

[ariesdude]

Are you sure the thermostat is installed the right way - in other words is it closing when its actually supposed to open?

[joetoken]

ok, i put it in with the spring part inside the motor, and the jiggler valve up, is that right?

[wytbishop]

Are you sure the fan is coming on when it's supposed to? Sheck the fan relay.

[ariesdude]

ok, i put it in with the spring part inside the motor, and the jiggler valve up, is that right?

That sounds right - other than that you may have air in the system or headgasket issues.

Open radiator cap and let the engine run for a while (with the heater set to max heat and fun to full) - any air trapped in the system will start bubbling out once the thermostat opens.

Also check engine compression...

[joetoken]

Runs like a bat out of hell other than overheating, I was worried maybe oil pump failing, I will try to purge air and see what happens, thanks

[joetoken]

Well, it is better, but still overheating up hill at 65 to 70 miles in hour,

to recap, I replaced above parts, and purged air out of radiator, I thought it was working, but still runs hot when running uphill at highway speeds for long distances, ie, when engine under long periods of stress

This is not quick, I basically drove 65 miles in the morning no problem, but at noon coming back about 30 miles into drive with ac on, it starts to heat up, then it goes to about 1/4 in from H on gauge

Temp is fine at low speeds in town driving, and all day, it just gets hot when I'm driveing fast?

[Bumpysbro]

ya check what wytbishop said, my fan relay got soaked in water and when it got too hot it would turn on and my car started overheating, happened again today when i messed with the intake and popped the relay off causing the fan not to kick-on on the highway.

[ariesdude]

Do you have oil in coolant or coolant in oil issues? What are the compression numbers? If everything else is fine - i would think that you may have a blockage in your cooling system - might help to try a radiator flush and possibly an engine (oil) flush too.

Another option - maybe you got a faulty thermostat from the store when you replaced it.... sounds unlikely, but i have been screwed by autozone before...

[joetoken]

I have flushed it senseless, coolant wise, I have never run anything but sythetic oil in it, I am starting to think it may be running too lean?

I am not sure what you mean by your fan comes on and your engine overheats? My problem only occurs on the highway and then only under stress, like a really long uphil grade.

I am wondering if there is something that would cause the engine to lean up the mix in that driving condition?

[wytbishop]

I once installed a 440 in a charger that was built by another engine shop and it overheated constantly and we couldn't figure it out at all....

It finally turned ou tthat the engine shop installed the cam incorrectly so even though we had it at full advance it was still 10 or 12 degrees retarded.

It's possible that your engine is not timed correctly. It's a long shot, but it came to mind so I thought i'd share.

[Custommx3]

Is it boiling over?

Your rad cap could be bad...



I found this..

http://www.tegger.com/hondafaq/overheating/index.html

[joetoken]

I changed radiator cap in addition to all the above and still overheating, the only thing I haven't done is fan relay? I noticed when looking up the fan relay that there is a fan thermostate listed, could that be a problem?

[PATDIESEL]

You should be able to check the relay and fan thermo by watching the fan go on and off. Just crank the car and let it sit until the temps go up enough that the fan kicks on. It should stay on for a minute or so and then turn back off once it has the temps down. If it comes on immediately after you crank the car then the fan thermo is bad. If the fan doesn't come on then the relay or the fan are bad. Make sure your pressure cap is the right rating and that the thermostat is working. I've seen brand new thermostats that do not work and I've seen guys who claim to have purged the air, not acutally have ALL the air out. It can take a bit for all the air bubbles to work their way up. You can gently squeeze the lower rad hose to help bulbbles come up. Also, to check the thermostat the lower hose should be the same temp as the upperhose when the car is warm. If the lower hose is cooler then the thermostat is not opening.
Timing can be an issue, but the car should not run correctly if the timing is off.

[Bochek]

just unplug the thermo sensor and short the wire to ground, the fan should come on. if it doesn't then either your fan or the relay is bad.

if it does, follow the shop manual procedures for testing the sensor.

- Bochek