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Coolant leak hazard

3K views 9 replies 4 participants last post by  rhall 
#1 ·
I had buried this problem in an obscure thread about cylinder head parts. I think it deserves its own treatment.

I am fixing a car that overheated and ultimately warped the cylinder head beyond Honda's limits for resurfacing. The car had a host of possible causes: broken water pump belt, failed rad cap seal, poor thermostat response and even a bad AC clutch. But I might have found out the source failure. It looks like the water outlet header was leaking at one or both rubber O rings at the pipes at the front. The overheating would have been caused by loss of coolant leading to other failures.

Those pipes were very stuck and after removing the chalky corrosion at the point of the O ring seal it was obvious that aluminum material was missing. I replaced that header with one from a donor engine but there was potentially a worse problem.

As you can see in the picture the plate covering the three high voltage connections below the header was almost completely eaten and had tapered down to the thinness of paper. In the picture the small break was caused by my fingernail but I could easily have broken off a large chunk. It was still sealing but would have corroded through very soon.

Who knows what would have happened if coolant had leaked into that electrical pocket. I guess the moral of the story is to eyeball that area every now and then. Does anyone know if coolant on those HV connections would be catastrophic?

Does anyone know if you can use plumber's grease or silicone on those coolant connection points? The O rings are a worry but actually, depending on how you count, there are 7-9 actual water to air points on that header. New, that aluminum header is $132 from Majestic. Maybe it would be possible to expand the steel pipe a bit to tighten the fit. This is a potential problem for our Gen1 Insights. Anyone want to comment?

Rick Hall
Caledon, Ontario, Canada
 

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#2 ·
Rick
I'm not trying to be dumb but maybe a picture not so close showing the headers/head attachment.
I'm trying to understand before commenting as I don't have the headers in front of me.

Good thread and pics so far.
Good job
Willie
 
#3 ·
I think he is referring to the manifold that bolts onto the back of the head (shown in illustration with yellow TDC). I'm guessing you are showing where tubing #11 & #8 connect to that manifold. This is right beside the area of the engine where the high voltage wires connect which is what he is showing in the other pictures I think?

Text Map Auto part Diagram World
 
#5 ·
Thanks Mark
As in picture 4?
Did you get my PM?

Willie
 
#6 ·
Opps. It's suprising how when you get involved with something you think it obvious to everyone. These pictures should help. Note the bent steel where the pipe mounts to the header. That was from prying with a screwdriver- the rubber was stuck behind a ring of corrosion on the aluminum.

One thing I should add: the rubber was pliable and seemed OK after rubbing off a lime-like deposit. The manual does say to replace them though.
 

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#7 ·
Those picture explain it best. The coolant "pipe" goes into the "TDC case" which is bolted to the head.
I would spray the end of the pipe and the O ring with a silicon spray after making sure the recess was clean. Also make sure the flange that the bolt goes thru to hold the "pipe" on......is about a 90 degrees angle to the pipe.
Like THURSDAY says, unless it is a drip drip, I wouldn't worry about it.

HTH
Willie
 
#9 ·
Rick
As always, check the coolant bottle for fluid level at least weekly. That would be the first sign of coolant loss. Make damn sure you bleed the system after filling with coolant.
Bleed with the climate control set at MAX. temp. and the blower fan on high.
That is very important.

HTH
Willie
 
#10 ·
Wiil do Willie. And for those people who are attempting to purge the cooling system of air- if it keeps burping you have to start suspecting the head gasket.

That's what I found and I confirmed it with a CO/CO2 chemical test. The liquid in the kit changes colour in the presence of carbon gas. The bung supplied was too large for our little rad cap necks so I rigged it to the air bleed pipe at the top of the coolant header. I used a Mityvac vacuum pump to draw up the gases.
 
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