Still adding coolant...

[MPR]

I did a search but didn't find much...

Replaced my BHG about 4 weeks ago now. I did everything properly. Used an oem style gasket and the stock head bolts torqued to 75ft-lbs. Engine is still in good condition and didn't need to be decked. Made sure everything was super clean before re-assembling.

Now 4 weeks after, I'm still having to add coolant to the reservoir every week as the light slowly comes on again. It's not blowing it out, there are no puddles or leaks that I can see anywhere. No white smoke and no "chocolate milk" in the oil.

Either the 7mge is the worst car for air pockets in the cooling system or the coolant is going somewhere... I ran the engine with the front of the car raised for quite a while with the rad cap off. Thought I had gotten all the air out, no?

I know many of you have done BHG's, is this common?


Thanks.

Mike.

 

[AJ'S 88NA]

Did you have the head surfaced and checked for flatness?

 

[MPR]

I didn't do that but I also didn't use a metal layer gasket, so it wasn't really necessary to do so. I used an oem style gasket, which is designed to compress and seal small imperfections, so long as everything is clean and clear of debris/oil etc.

There is no sign of coolant in the oil (or oil in coolant) and no white smoke.

 

[hvyman]

The head should be checked for cracks cleaned and machined for any hg job. Only the smoothness of the machine job matters for the style of hg.

Head could be cracked.
Hose could have a pinhole.
Heater core could be toast.

Have you pressure checked the cooling system?
Have you done a compression test?
Have you done a block test?

 

[MPR]

Compression test, yes. ~180psi across all 6. The head was thoroughly cleaned by yours truly. It was not machined because the engine had no signs of overheating and I didn't have the time or money to take it in to have it machined. I've seen many HG's done this way in the past and they held/lasted no problem.

If the head was cracked, would I not see it leaking into the oil or on the ground or see while smoke?
If a hose has a pin hole, would I not see it leaking and smell coolant under the hood? (which I can't and don't)
If the block was cracked, would I not see it leaking in the oil or on the ground?
If the heater core was toast, wouldn't I see coolant leaking into the interior, smell coolant and or see it leaking on the ground?

Not trying to undermine your suggestions, just trying to be logical...

 

[hvyman]

Yes it's possible to have leaks without smelling or them being super noticeable.

But according to you you have no leak.

Pressure test the. Cooling system to like 16 psi. Should be able to see the leak then.

 

[MPR]

Alrighty, I'll pressure test the system and reply back with the results.

Thanks for the suggestions.

 

[jake8790]

Check all the hoses. I had the same problem and it was a small hose way down under the intake manifold slowly leaking. If there aren't any air bubbles coming up from the hose in the reservoir, the HG is probably fine.

 

[mecevans]

If you still cant find it with the pressure test, UV dye is the next step.

 

[MPR]

I haven't yet tried the pressure test...

Have a feeling that maybe this is just the way it wants to be (for some odd reason). Even when I run it for a few days with the bird cage lit, when I pop the rad cap, it's still full. Temp gauge also stays steady, half-way up the gauge when it's warmed up. Never seen it go any higher.

Have to do an oil change soon. When I do that I'll do a very thorough look-over under the engine to try and see if there is any trace of coolant leaking from somewhere.

Will update this thread when with my findings...

Thanks again for the suggestions/tips.

 

[MPR]

Update: I ran it the past few days (4 days or so) with the bird cage lit and the coolant level has dropped in the rad a bit... I've got a leak somewhere, just gotta find it. At least I can rule out the head gasket...

 

[AJ'S 88NA]

Maybe yes...maybe no^

 

[MPR]

Maybe yes...maybe no^

The hg was just replaced back in late November/ early December. Oem style gasket (not a metal layer gasket), everything was cleaned up and examined thoroughly. Head bolts were torqued to 75ft-lbs. No smoke, no oil in the coolant and no coolant in the oil.

 

[SupraSean]

Carpet wet? x2 on a rad psi test

 

[MPR]

The heater core is on my radar as a possible suspect. Though I hope it's something else. Something easier to replace/fix...lol. Carpet is dry other than when I bring snow in on my shoes. There is no coolant smell inside the car at all.

If I don't find any evidence of any leaks from underneath when I do the oil change this weekend, I'll try and get my hands on a pressure tester for sure. I can smell coolant from time to time, so that to me indicates it's an external leak and not internal (hg).

 

[IndigoMKII]

It could be possible that it is leaking and evaporating before it 'drips'.

 

[MPR]

Call the news paper! I've got a 7mge that doesn't leak coolant! lol

Found the leak. It was the hose on the driver side where it connects to the heater core near the brake booster. I had to watch it with a light and rev the engine at the same time. Saw it leaking out, only when revving. The stock pinch clamp wasn't doing the job so I jammed a hose clamp on and it's good to go!

Thanks again for the suggestions and tips.