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-   -   Might have a blown headgasket (https://www.subaru-svx.net/forum/showthread.php?t=64676)

Huskymaniac 08-31-2018 02:24 PM

Might have a blown headgasket
 
Since the facebook guys don't seem to want to post my issue, I will try here.

Here are the facts:

1. The temp gauge is occasionally rising above normal.
2. After the car cooled after the first time my son noticed this, I checked the coolant level. The radiator wasn't full to the fill neck. I topped it off with a couple of cups of coolant.
3. After topping off the radiator, I drove the car 100 miles up and down hills in northern central PA. The car didn't get hot AT ALL.
4. Fans are working.
5. After a couple of days of driving back and forth to work (20 minutes each way) I saw the temp gauge climb again. Again, the radiator was not full. However, the overflow tank was more full than it was previously. I topped it off again with quite a bit of coolant. It drove home with no overheating.
6. I bought a new radiator cap. When I went to install it, I noticed the radiator was not full again and the overflow tank was full to capacity.
7. I installed the new radiator cap and transferred some coolant from the overflow tank to the radiator.
8. I ran the car at idle until the fans came on. I saw no bubbles in the overflow tank. The temp dropped like a rock when the fans came on. It didn't overheat.
9. I see no oil in the coolant.
10. My mechanic pressurized the cooling system and said it held pressure for 30 minutes and he didn't see any obvious leaks.

So, I will see if the radiator cap helps. If not, I suppose the inevitable finally happened. Any other ideas or comments?

Blacky 08-31-2018 07:03 PM

Re: Might have a blown headgasket
 
Keep an eye on the gauge. If it's overheating you should see bubbling. Has it been hot as hell there like it has been here in Quebec?

SURTEESS 09-01-2018 03:02 PM

Re: Might have a blown headgasket
 
Have you recently changed cooling fluid ?

If so then you need to burb the system, normally by jacking up the car (from front or rear - someone else confirm which one).

Then while jacked up fill the cooling areas.....


I find it interesting that the radiator is low and the overflow is ok ? - is the rubber pipe between them blocked or split, as the overflow should take up the lack of any water in the radiator.

92 SVX 09-01-2018 04:17 PM

Re: Might have a blown headgasket
 
To be honest in my personal experience it does sound like the first signs of a blown head gasket.
The combustion pressure is slipping into the cooling passages (very very slight though at this point) it is displacing the coolant to the overflow tank since its only a very small amount at this point it isn't enough to push it out of the overflow tank yet. and why it passes the pressure test the combustion pressure is pushing from the cylinder to the cooling system and its very high pressures, pressurizing the cooling is (at this time) actually pushing the gasket into place sealing it better.

And since the problem is very very slight right now the car won't over heat until enough coolant is removed from the system to be low on fluid.

svxcess 09-01-2018 10:01 PM

Re: Might have a blown headgasket
 
.

Also check the bottom of the reservoir for clogs or debris. I have seen coolant pumped into the reservoir, under pressure, from the radiator when the engine is hot.

As the engine cools down, the radiator should draw the fluid back from the reservoir which is normal. however, if there is debris at the bottom of the reservoir, it may keep the fluid from draining back.

Repeated cycles just keep the fluid entering the reservoir (and filling it)

Easy to remove and check.


But I did experience head gasket failure back in 2009 with 122,000 miles.

.

svxcess 09-01-2018 10:17 PM

Re: Might have a blown headgasket
 
Quote:

Originally Posted by SURTEESS (Post 749208)
Have you recently changed cooling fluid ?

If so then you need to burb the system, normally by jacking up the car (from front or rear - someone else confirm which one).

Then while jacked up fill the cooling areas...

I find it interesting that the radiator is low and the overflow is ok ? - is the rubber pipe between them blocked or split, as the overflow should take up the lack of any water in the radiator.

Jack up the front of the car as high as you can. Tom Krynock used to use his frame lift and raise the front of the SVX as high as possible, leaving the rear wheels on the ground. Even driving up onto ramps or jackstands works.


I had a shop use this tool on my Outback with great results. Uses vacuum to exacuate all the air from the cooling system and draw in 100% new coolant without air pockets.

https://www.amazon.com/UView-550000-.../dp/B0002SRH5G


See the video here of how it works.

https://youtu.be/_WCRcuCZI50

Huskymaniac 09-02-2018 03:05 PM

Re: Might have a blown headgasket
 
Quote:

Originally Posted by 92 SVX (Post 749209)
To be honest in my personal experience it does sound like the first signs of a blown head gasket.
The combustion pressure is slipping into the cooling passages (very very slight though at this point) it is displacing the coolant to the overflow tank since its only a very small amount at this point it isn't enough to push it out of the overflow tank yet. and why it passes the pressure test the combustion pressure is pushing from the cylinder to the cooling system and its very high pressures, pressurizing the cooling is (at this time) actually pushing the gasket into place sealing it better.

And since the problem is very very slight right now the car won't over heat until enough coolant is removed from the system to be low on fluid.

The last part makes perfect sense. What confuses me is that there is no oil in the coolant. Also, why doesn't the air get pushed into the overflow tank and coolant sucked back in when everything cools? To see what I am seeing, exhaust would need to get into the system and push coolant into the overflow and little to no coolant get sucked back into the radiator when everything cools.

92 SVX 09-02-2018 05:20 PM

Re: Might have a blown headgasket
 
Quote:

Originally Posted by svxcess (Post 749212)
Jack up the front of the car as high as you can. Tom Krynock used to use his frame lift and raise the front of the SVX as high as possible, leaving the rear wheels on the ground. Even driving up onto ramps or jackstands works.


I had a shop use this tool on my Outback with great results. Uses vacuum to exacuate all the air from the cooling system and draw in 100% new coolant without air pockets.

https://www.amazon.com/UView-550000-.../dp/B0002SRH5G


See the video here of how it works.

https://youtu.be/_WCRcuCZI50

Yes I have this tool, it makes it very easy to refill the system perfectly without any issue with burping the system. But even more importantly it is a great tool to check the system, since if there are any leaking spots it can not pull vacuum nor hold that vacuum.
Quote:

Originally Posted by Huskymaniac (Post 749222)
The last part makes perfect sense. What confuses me is that there is no oil in the coolant. Also, why doesn't the air get pushed into the overflow tank and coolant sucked back in when everything cools? To see what I am seeing, exhaust would need to get into the system and push coolant into the overflow and little to no coolant get sucked back into the radiator when everything cools.

There will rarely ever be oil in the coolant unless the headgasket is completely trashed, or if your rings are totally shot. Since in normal combustion there will not be oil in the combustion chamber.

And as to the coolant pushing into the overflow then getting sucked back, yes in normal operation that is what happens, however that relies on heated coolant pushing out, and cooling coolant inside the engine contracting creating a vacuum to pull the coolant back. but if the exhaust gas is seeping into the coolant those gases are displacing the coolant, thus no vacuum is occuring.

Huskymaniac 09-04-2018 01:29 PM

Re: Might have a blown headgasket
 
Quote:

Originally Posted by Blacky (Post 749207)
Keep an eye on the gauge. If it's overheating you should see bubbling. Has it been hot as hell there like it has been here in Quebec?

It has been hot and continues to be hot. I am hoping it is a bad rad cap or a clog like John mentioned (haven't checked that yet) but I am not optimistic.

I need to decide what to do if it is a blown gasket. It will cost me about $1800 to get it repaired. It is a 96 with no rust at all and runs well otherwise. It has 149K on it so I think I can get another 50K and probably three or four years if I reseal it. That is definitely worth $1800. But I will be driving a car with crappy clear coat and several dings and scratches around for 3-4 years. Not sure I want to spend $1800 to do that. Do I spend an additional $3K and get it repainted too? Then it would look less ghetto. But now I probably need to get at least 5 years out of it to make it worth while. Tranny is original so will I get 5 more years? And, even if I do, will I want to drive it around daily when it is pristine? I suppose I could go all out and turn it into a garage queen and bring it to car shows. Not sure if I am a car show guy though.

92 SVX 09-04-2018 04:01 PM

Re: Might have a blown headgasket
 
Quote:

Originally Posted by Huskymaniac (Post 749242)
It has been hot and continues to be hot. I am hoping it is a bad rad cap or a clog like John mentioned (haven't checked that yet) but I am not optimistic.

I need to decide what to do if it is a blown gasket. It will cost me about $1800 to get it repaired. It is a 96 with no rust at all and runs well otherwise. It has 149K on it so I think I can get another 50K and probably three or four years if I reseal it. That is definitely worth $1800. But I will be driving a car with crappy clear coat and several dings and scratches around for 3-4 years. Not sure I want to spend $1800 to do that. Do I spend an additional $3K and get it repainted too? Then it would look less ghetto. But now I probably need to get at least 5 years out of it to make it worth while. Tranny is original so will I get 5 more years? And, even if I do, will I want to drive it around daily when it is pristine? I suppose I could go all out and turn it into a garage queen and bring it to car shows. Not sure if I am a car show guy though.

Cant speak for the trans but I can tell you if you reseal the heads( and have it done right) you should get a lot more then 50k and 5 years. If you make sure the water pump inlet is enlarged, and or move the T-stat to the other rad hose you should not have any issue with head gaskets again. and since there are stock engines (without those fixes) lasting high into the 200k's I wouldn't worry over much.

92 SVX 09-04-2018 04:12 PM

Re: Might have a blown headgasket
 


This is a how to to find out if the head gasket is leaking combustion gasses into the cooling passages.

Disregard the rattly noises, bad bearing in the power steering pump.

Here is the Tester I own and use, but any shop will have one, or any of this type will help.

The blue fluid when in contact with the carbon-monoxide (I believe is the gas that does it) turns green if just a small amount, or yellow if large leak.

https://www.amazon.com/UView-560000-...on+Leak+Tester

Huskymaniac 09-05-2018 07:38 AM

Re: Might have a blown headgasket
 
Quote:

Originally Posted by 92 SVX (Post 749244)


This is a how to to find out if the head gasket is leaking combustion gasses into the cooling passages.

Disregard the rattly noises, bad bearing in the power steering pump.

Here is the Tester I own and use, but any shop will have one, or any of this type will help.

The blue fluid when in contact with the carbon-monoxide (I believe is the gas that does it) turns green if just a small amount, or yellow if large leak.

https://www.amazon.com/UView-560000-...on+Leak+Tester

Thanks man, I will give that a try. I needed to buy some stuff from Amazon anyway.

Well, the rad cap is not the problem. New OEM cap and it overheated on the way home yesterday. I will check for a clog like John suggested and order the tester but I suspect it is a gasket. Seems logical to get the engine re-sealed at this point. I just need to decide if paint makes sense.

svxcess 09-05-2018 09:45 AM

Re: Might have a blown headgasket
 


Quote:

Seems logical to get the engine re-sealed at this point.
And the perfect time to do the timing belt, idler pulleys water pump and plugs, if they need to be done.

And since the intake manifold is off, the PCV valve too...

.

Huskymaniac 09-06-2018 06:03 AM

Re: Might have a blown headgasket
 
Quote:

Originally Posted by svxcess (Post 749248)



And the perfect time to do the timing belt, idler pulleys water pump and plugs, if they need to be done.

And since the intake manifold is off, the POV valve too

.

PCV was just done. Tom did the timing belt, water pump and cam and crank seals about 40k miles ago. I need to check when the plugs are due. Will all the vac lines be exposed? They are all original.

Sean486 09-06-2018 12:15 PM

Re: Might have a blown headgasket
 
Quote:

Originally Posted by 92 SVX (Post 749244)


This is a how to to find out if the head gasket is leaking combustion gasses into the cooling passages.

Disregard the rattly noises, bad bearing in the power steering pump.

Here is the Tester I own and use, but any shop will have one, or any of this type will help.

The blue fluid when in contact with the carbon-monoxide (I believe is the gas that does it) turns green if just a small amount, or yellow if large leak.

https://www.amazon.com/UView-560000-...on+Leak+Tester


Nice. I may pick up one just for the hell of it. Necessary tools for a Subaru owner!


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