racerock

This whole cooling issue has been driving me nuts for a while now. Never before has any troubleshooting been going on this long for me - regardless the car, component, etc...

Started last winter where we noticed that the heat took a while to warm up, but once it did, car ran fine, heat worked consistently, etc. Level was o.k. back then (but in hindsight - was it slowly getting low over time? I did not think so at the time) My wife drove it mostly, but I did drive it often enough to watch the gauges, how it ran, etc.

A few months ago, I started driving it more, because I wanted to check out a few things - including this heat situation since it was getting colder out. Good thing I did because it started to get hot - right after the engine would heat up. The delayed heat was still the same. After the gauge would get up to the line before the red zone, it would quickly go down.

I think the coolant level was a little low, but not dangerously. Once it returned to normal, it would run fine and not heat up again.

SO: I replaced the thermostat - as it seemed like it was getting hung up on opening. Classic symptoms. Bled the system, checked the hoses some. Put everything in. Outcome: Heat came on much faster, thought it was fine. UNTIL: a few days later then wham - the needle started going close to the red zone again.

SO, I bled it again - no fix.

Suspected the Radiator - It now seemed to act like a radiator that had its lower tank (vs side tanks) that had the core fins clogged all along the bottom... So I did replace the radiator - found a good price on a new one that seemed to be decent quality and an exact match.

SO, then I checked out the fan circuit - seemed like they were not kicking in right. I also ran down the road and monitored the temp, oxygen sensor, etc. using my scan tool. Things looked fine.

Fan Circuit - relays kicked in the fans o.k. by jumping the sensors to kick them on - tested the oil temp circuit. Turn on the A/C and they both fire up.

I did notice that the oil temp switch acted funny testing it in water on the stove, and in testing the resistance of the sensor that feeds the computer - it seemed off by about 10 degrees - So I figured I would order new (I did and tested them before installing) - Ordered new Honda sensors - they are in as of last night.

Then I start seeing stuff about the original thermostats - and to be honest thought that maybe the Stant one may not perform exactly like the original as they did look very different (Stant looked like the traditional thermostat - which I thought was an o.k. thing when I bought it - and probably do so today...) I thought that maybe it had something to do with it in conjunction with the sensors above. - So a Honda Thermostat is in it as of last night.

Then I tested the radiator cap - Here is where I figured the culprit was found - It would not release the pressure. So, I add that to the list of parts to order... Figured this was it. So, as of last night - a new Honda cap (tested perfect before putting it in) is in the car.

I also pressure test the cooling system - it held pressure - so I figure that the head gaskets are o.k. - but I have some doubts.

Then while ordering parts - figured that there could be a slim chance that the lower radiator was collapsing at speed. So, as of last night - new upper, lower and small hoses with letter B through F are installed (still need to put A and B - on the back of the motor)

So, bleed it, top it off. Figured it would be fine today. Happy as a clam...

NO friggin dice: Monitored the overflow carefully last night after wiping it off really good - and nothing was coming out last night.

Drive to work today - nothing coming out when I get there. Check in at lunch - nothing there. Drive around at lunch I noticed that it stopped blowing hot air out the heat (something it does before it purges coolant out the overfolow, and I started to see some seepage after returning. Not much, but some.

Drive home - SURE ENOUGH - get on the highway as I watch the temp needle go over where it should be - then drop back down (after shutting off the engine and coasting)

Park it at home and go out after letting it cool. SURE ENOUGh - check the coolant level in the radiator and it is low. THE OVERFLOW BOTTLE - it is full all the way, and there is coolant that is overflowing.


I am at my wits end. Any suggestions?

racerock

By the way, I am suspecting the Head Gasket - but am hoping not...

lankanboy1

Check the hose that goes to the over flow Bottle. I had allmost similar problem i fixed it by replacing the Radiator Cap.

Go90go

+1 on a messed up cap.

~Cheers~

meazz1

It's the cap, I think.
Did the new radiator come with a cap?

racerock

-3 on the radiator cap. I had thought for sure it was the cap as well...

From the post above (I know it was a long post...)

The new cap tested perfectly - released the pressure at the right point exactly. Still flows into the overflow.

Based on some further checking and driving - I'm leaning more and more to the head gasket. With the radiator filled, overflow empty - it fills up the overflow halfway after about 22 miles of driving and then parking it , and letting it cool.

So, I put the coolant back in the radiator before driving home... Will be doing a compression test tomorrow. But, I have seen C. Tests not pick up a head gasket before. And sometimes the leakdown testor is not accurate either...

racerock

Just as with other head gasket failures, a compression test did not really yield any positive results - around 180 in all cylinders, very well balanced.

Yanked the head off - and sure enough, you could see on cylinder #5, there was a leak. A couple others were right behind it.

SO, the head is shaved, hopefully getting everything back together in a couple days.

Let me tell you, it takes a decent amount of time to get the heads off. I ended up taking off the Y pipe and pulling the heads with the exaust manifold on it. There is no way you can easily get the exhaust manifolds off with the heads in the car...

Went ahead and bought a new timing belt - it only has about 40K on it...

meazz1

Glad to hear you got to the bottom of the issue.
Where are you getting your head from?

When I replaced my engine, they also told me that it only has 39k, but no way to prove it.
Car drives great but engine does not look to be 39k.

racerock

I'm using the original heads - no real problems there. I did have the heads shaved, just to be sure. There was a second cylinder that was very close to starting to leak in looking at the pattern on the head.

I'm going ahead and putting in a new timing belt - even though mine has less than 40K on it.

I also want ahead and changed the 3 heater hoses and the small hoses that are a bear to get to in the back of the engine.

If I were you, I would consider putting in a new timing belt, if you are not 100% sure of the history of the motor...

meazz1

Oh, I have put in all new belts, seals when the engine was out.