vayankee

Or you could add some dye to the cooling system - a bottle runs about 10-15 dollars.

4HondaOwner

I have a leak from one or more of the the o-rings under the intake manifold and it will be fixed later this week. When the engine cools down, it by physics sucks air into the system. I've had to bleed mine out several times using my Lisle Funnel.

If you shine a flashlight to the right of the thermostat housing and see black or green crud under the intake manifold, odds are like my car, you have a o-ring leak.

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tjsilvasr

Would air in the cooling system cause the heater to blow cold air ?
And do the fan switches sometimes function intermittently before they go out ?

4HondaOwner

Yes

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tjsilvasr

I think my head gasket is blown. No white smoke but the engine gets hot and blows out into overflow. But it seems like fan don't work right sometimes, like last night I changed the fan switch on radiator and went for test drive all was good. But when i slowed down and stopped to head home it started getting hot so I jumped out and looked to see if fans were on they were not, so i turned on ac and fans came on. Still not in red zone so i turned around for home and temp dropped down but got hot again when in low speed area a block from home not red zone but hot. Pulled in it peeked blows out overflow.

vayankee

I would not too quickly conclude that the head gasket is blown. Coolant forced into the reservoir is just a sign of air in the system. And air or steam will punch the temp gauge up for sure. If you have opened the cooling system for any reason - changing out antifreeze, thermostat, whatever, you have to get the air out of the system. Follow the instructions in the owner's manual or the online manual on this site (in the first page posts of this Forum), and see what happens with the temp.

Of course the fans not coming on when the engine is hot will also lead to overheating. There's a sensor at the bottom right of the radiator-it's exposed to the elements so that may be bad, affecting the fans' operation.

tjsilvasr

Week 1. Intermittent spike to hot "red zone" on temp gauge engine not overheating at all let it cool down temp still high on gauge. I checked the temp gauge sender it was bad changed it all was good.

week 2. Noticed coolant around cap and down the inside face of radiator so I changed the cap. Next day I check it an all is good. Following day i go to do some work on A/C compressor seals. I got it working great with that es12a Advanced "Great stuff" I then notice a puddle of coolant on top of lower tank of radiator. Looked like the upper hose was cut so I trimmed and it and ordered new ones. Top dried up but tank and shroud on fan still has coolant wetting in some areas.

Week 3. It’s a old cooling system and has seen better days so I got a new radiator, hoses, thermostat, trans cooler lines and "I was a bad boy and got peak 50/50 coolant. Keep in mind all was well no overheating just a little wet, so I didn't get any other sensors. Test new thermostat and put it all in. Did the bleeding like the book says and sat in garage for about 30 min running it through its cycles watching fans go on, off, on. Ran it with heater on AC on all was good shrouds on everything dbl checked bolts all good. Went for test drive about a mile turned in a parking lot and checked for leaks and it started getting hot. Still no fans because radiator is not hot. Turn on AC fans come on but no change in temp gauge jump in and head back home temp starts to drop till I start to slow down and it starts getting hot again and got home and it was a hair from red zone and blowing out in to over flow. I let it cool bleed the air again and again got 2 new sensors 1 fan switch and the other one on manifold passenger side bleed it again and still the same. Oh yah last night the fans wouldn’t go off, I had to turn the ignition on for it to stop but when I turn the key off it went back on. I waited for 5 min and still on, good thing I didn’t just go in the house. I finally turned on ignition so they would go off turned on the AC and turned off the key and finally it shut off.

Pulled thermostat just now and tested it again thinking maybe it locked up but no luck. I ordered the no spill funnel and hope that will do it but will see.

vayankee

You have done a lot of work on the system. That suggests air trapped as a likely cause. Using the Lisle funnel will help. It takes at least an hour of work but that may do it.

But, you also mentioned "the fans wouldn’t go off." From my understanding, that is a different problem. You can check the online service manual for diagnosing that issue. Try page 1066 to start.

Now, there's always the chance of a leak that you don't see. Have you considered a pressure test? And/or using radiator dye?

4HondaOwner

You didn't use Honda Type 2 coolant.

I would have. Most of us do.

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tjsilvasr

so where can I find this on line manual at ?

tjsilvasr

Thanks, thats ok the page 1066 is the same as the one on my pdf file, I got it on my phone...

tjsilvasr

I got AC dye if I could keep the coolant from blowing out the overflow..

So you said It takes an hour of work with the Lisle funnel ?

4HondaOwner

20 minutes with the Lisle Funnel. Best $30 I've ever spent.

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vayankee

I think that the time needed with the Lisle depends on the amount of air and where it is trapped.

On leaks, there are 22 hoses plus o-rings that can go. Also, when you have everything apart to get at the hoses, you can clean up the EGR system, which can be a real threat as far as overheating goes.

Yes, blowing out coolant will probably diminish the chances of spotting a leak that way, but what have you got to lose, is the way I look at such things.

tjsilvasr

I have done so much since my last post and shes still blowing coolant in to the overflow.

1) got the magic funnel and burped her for an hour several times. no help
2) replaced thermostat and TW sensor again just ic case one was bad. no help
3) pressure test cooling system, found a minuscule leak on top hose fixed it. test ok
added UV dye to system and ran it for 5 cycles of fans. no signs of dye
4) ran cylinder leakage test. all cylinders with 20 psi was 20% +- 2% and pegged when rotated to TDC.
5) I ran a second test on cylinders but this time I setup pressure tester on radiator with 10 psi to see if it would increase with 30 psi in cylinders. no change
6) running out of ideas so I ordered a UVIEW 560000 Combustion Leak Tester. Tester should be in by end of week

I have been thinking maybe the FCU is bad or maybe even water pump. any thoughts ?

The timing belt and water pump was changed at 116k by the previous owner and she is currently at about 160k.

!! I am so confused, don't know what to think anymore !!