2G Air pressurizing coolant through fiav?

[djseclipse]

Recently changed throttle body to a s75. I did not block off the fiav. The problem is that I'm having coolant overflowing from the resevoir only after the engine shuts off. I'm not noticing any oil in the coolant or vice versa. Changed the tstat and cap. Car does not overheat and seems to run fine. Compression is great across all cylinders. Could that weird gasket for the fiav be allowing air in or looking at a head gasket? 125k miles and head has never been off the car

 

[Vegas Smith]

Fans not working?

 

[djseclipse]

Yes fans are fine.

 

[djseclipse]

I ordered a new fiav gasket, but it seemed to big for the s75. I think I'm going to disassemble it again and check this gasket. I don't see any coolant leaks in this area, but air could still get in? I don't recall having this issue until after I installed this tb. Any other suggestions?

 

[91talonts1]

I suppose the cooling system could be pressurized if the fiav o ring failed in the right way. I don't think that's your problem though seems it would only be pressurizing it under boost, or drawing coolant in the intake under vacuum. Shutting the car off shouldn't have any effect on the fiav that I can think of. Just temperature.

 

[djseclipse]

The weird part is that it doesn't always overflow, but when it does the coolant is really bubbling in the resevoir. The resevoir is always completely full even if the car has been sitting for weeks.

 

[91talonts1]

Are you filling it back up after it pushes it out? What do you mean by completely full?
The way the system works is as your coolant heats it expands and goes into the reservoir. As the engine cools the coolant that has expanded to the reservoir is sucked back up through the overflow hose. If you fill your reservoir up all the way or at least past the point it should sit naturally on a cold engine it's always going to be pushing some out.
To simplify there should be empty space left in your reservoir for the coolant to expand into.

 

[djseclipse]

I only filled the resevoir barely halfway. When it overflows the coolant is at the very top of the resevoir and doesn't get sucked back in even after sitting for long periods.

 

[91talonts1]

If it's still completely full after sitting till it's completely cool, drain it back down to halfway. Run it again to operating temp then cool again and see where you're at.

 

[91talonts1]

Also make sure you don't have air trapped in the system. The cooling system on a DSM should self bleed, but I've seen a few threads on here where guy's had terrible with that.

 

[djseclipse]

Ok. I will try that. Thanks!

 

[djseclipse]

Update: I burped the system, drove about 10 miles and parked it. Coolant still bubbling in the resevoir and overflowed. Today I did a compression check. Let the car idle til it was warm. Then performed the test. 165, 140, 145, 150. That's 1 through 4. I just did a compression test back in April 2016 and had 170 to 175 all across. I have only driven it 1k miles in the past year. So, I'm guessing head gasket? Car runs great, oil looks normal, and so does the coolant. It has a slight ocassional miss at idle but very slight. All plugs looked similar and normal. Thoughts?

 

[wishihadatalon]

It's possible that it would be your HG but I'd check all of the hoses, thermostat function, and the radiator cap first. Any of the hoses collapsing or having the smallest of leaks will result in this. If the radiator cap is defective or the seal is shot, I'd expect some pressurizing of the overflow.

 

[djseclipse]

I just installed a new tstat and cap. Does the compression not look off?

 

[91talonts1]

It's possible but those numbers don't look that far off. Was the engine fully warm when you did the compression test? If not you'll get skewed readings like that.

 

[djseclipse]

I just did a idle warm up and didn't drive it

 

[djseclipse]

Alright. Drove the car today. Did 2 more compression tests as soon as I parked it. Averaged 178 155 160 178. Concerned about cylinders 2 and 3. Seems like symptoms of a hg? Also heard a gurgling sound behind the j pipe near where the head and block mate after the car was shut off.

One more thing. I checked the timing marks on the cam gears and they are not set properly (see picture ). What does this mean? Otherwise the car runs good and is very stout. Should I pull the head and retime it?

 

[jakk220]

I would do a leak down test first. Did you open the radiator cap and check for bubbles in the coolant while you were doing the compression test? That is a pretty dead give away too. Also the timing marks do not necessarily line up every rotation. Did you spin it a few times and try to get them to line up?

 

[djseclipse]

I did remove the cap and start it up. No coolant came out, just some small bubbles as it flowed through. I don't think those timing marks will ever line up. Look closer at the marks, they are in the same position on each gear.

 

[jakk220]

If you take the radiator cap off and start the car on a cold engine and see bubbles that is a bad sign for a head gasket. If you take the cap off and do a *Leak-down test* (last post said compression test for some reason ) and see bubbles that is also bad. So if you do a leakdown test check that as well.

 

[djseclipse]

Here's another picture of the timing marks.

 

[jakk220]

I believe you are looking at the wrong mark on your exhaust cam. The timing mark should be in the groove not on the tooth.

Like in this picture where someone had the timing off.

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[djseclipse]

Oh. Thanks I just realized that mark was on the tooth and not the groove. I will check that out. Meanwhile I will get a leak down test done and see if it's the hg. If so, time for some arps and cams! Thanks

 

[jakk220]

No problem. I fought leaky head gaskets for 2 years replacing it 4 times before I finally figured out what was going wrong .

 

[djseclipse]

Didn't want to start a new thread, so I checked the proper cam timing marks and they appear to be off but the pins look to be in the correct position. Thoughts? See pic

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