Losing Water ( head gasket gone? )

[scouttster]

Hi all-
I finially got around to my heater core issue whereas I had steaming on my front windsheild. ( posted a couple months back ) Instead of purchasing sealer stuff, I bypassed the heater core hose back on itself and thought that was the end of my issue. However, I am still losing water and now think I may have a leak through the exaust. I tried the suggested method by Takza ( thanks ) to start it up and look for bubbles in the radiator and I didnt see any.

Also, I dont have a good fit ( plastic cap is in bad shape ) on the water bottle ( radiator cap is fine ) where that small hose leads to the radiator to the bottle and wondered if that could be the reason why I am losing water? Can I fill the radiator up to the brim and block off that small hose ( tape it closed off ) and if I lose water after doing that then I will know its the head gasket or crack in the block somewhere..

thanks

[takza]

What I do when in doubt about coolant issues is to pull the overflow tank out along with the hose to the rad cap area...and clean them out with a hose...put it all back together making sure the hose is good and the ends are sealed. Refill the tank to approx the fill line...then drive it a few days to stabilize the level...THEN use a marker to draw a line on the tank exactly where the coolant level is after sitting overnight. This way you can see how much you are using....if your rad cap is good.

You need the overflow tank in the system...otherwise you LOSE rad fluid. You need to have a hose to the bottom of the overflow tank and a good seal with the hose to the rad...and a good rad cap. The cap on the overflow tank isn't all that important as long as the hoses are good.

My wagon has been using a little...maybe an avg 1/2" of coolant every month or so for the last 70K miles or so...I keep some BarsLeaks in it due to some slight coolant smell from the heater core now and then.

Areas to watch for leaks are the top and bottom rad hoses...the tube under the thermostat....etc. The rad hoses I've tightened...I recently had a small leak at the tube and after adding a bit more BarsLeaks it has stopped. I redid this tube maybe 60K miles ago.

One way to check for leaks is to start the car up from cold and let it warm up to just under the middle mark...maybe 1/3 up the gauge....this is enough to build up pressure...but not so hot that the coolant evaporates...then you might see leaks with a flashlight.

The problem with BarsLeaks is that it eventually mostly ends up in the coolant tank.

[scouttster]

I just looked through the spark plug hole on all Cylinders. I see cylinder 4 - the top of the piston is shiny and clean.. Somehow water is getting in there.. I always thought when a head gasket is gone you will see a white frothy mix in the oil on the dip-stick.. I'm not seeing that in this case. So, how can I know if its the head gasket or a crack in the head / block? From pasts post I have read and working on the car over the last year I see its not a big deal whereas this motor is so easy to work on. I think I read on 1 post ( maybe petros ) he can change the head gasket in 4 hours..

[takza]

That would be an indication of a coolant leak I'd say....gasket or crack in the head. Depending on where the leak is...you can have a coolant leak into combustion chamber...or oil into coolant...and probably both.

I couldn't do a head gasket in 4 hours and do it right. They can test a head for cracks at a machine shop...or you can use a blue dye to do it yourself...but can't be sure you will find one.

If I was going to do one...I'd pull it off...then find a shop that did good work and take it in and let them do it right...if I was going to keep the car. Or you could do it the easy way...pull the head/manifolds off and hand lap the valves...new valve seals...check the head to be sure it was flat...put it back on with a new gasket...and hope you got it right.

[Petros]

Yup, that was me. My modified engine had a problem with head gaskets and I got pretty good at it, 3 to 4 hours total working time to replace the head gasket. That assumes your head is not warped or cracked, and you only need to replace the head gasket and nothing else. These heads are way easy to pull compared to the twin cam Toyota heads.

If it is only a slight leak you can actually continue to drive it as long as you always have coolant in it. You only get milky oil with a blown head gasket if coolant leaks into the oil passages, if it is only leaking into a cylinder, that the only issue is you have to keep enough water in it to keep the engine cool. I drove with a leaky head gasket for a whole year, I just topped up the coolant at every tank of gasoline.

If it is not too bad you might try the Barsleak head gasket repair sealant (not normal stop-leak, cost much more and requires the sealant to cure overnight before you refill it with coolent). IT works as a pretty good intrim repair.

It is pretty rare to have a cracked head or block (though it can happen), more likely it was overheated. If you ever do replace the head gasket make sure the head surface if flat to 0.002" with a good straight edge and feeler gauage.

IF you do replace the head gasket I highly recomment doing the modification to it by adding a couple of extra coolant holes as I outlined in an earlier thread. EVen with a stock gasket it keeps the area around the exhaust valves cooler and lower the risk of a future gasket failure. I also recommend only using either a Fel-Pro or factor head gasket, many of the aftermarket ones are junk, espcially the commie made ones.

Good luck.

[gatemaster]

When mine was leaking the car would slowly overheat in the summer especially going up hills and with the ac on. I did the coolant hole method Petros mentioned except I did all the holes. I no lnonger overheat no matter what the conditions are.
I sanded the slick surface off the new head gasket and coated both sides with permagasket aviation.

[Petros]

I would never alter the surface, or add sealant to a head gasket, unless it is specifically called for (as in an all copper head gasket). On all engines with aluminum and steel in combination, they apply graphite to both sides of the gasket (that silver/gray coating on it) to allow the head and block to move slightly relative to each other. The interface between the head and block handles the most pressure and had the larger temp differential of almost all other gaskets. To be a reliable seal the head gasket has to work as designed.

Before the graphite head gasket, aluminum engines, or aluminum head and cast iron block, head gasket failures were common. My dad had one of the first all aluminum v-8 Buick when I was a kid, and it needed a head gasket once a year. Of course he sold it soon after learning that, too bad GM had not thought that one through, they were way ahead of the time but they had not advanced gasket technology to make reliable what could have been a great advancement in engine design.

Since the block and head have to free to slide (due to very different temperature gradients) without damaging the gasket, I always sand the top of the block and the face of the head with 800 grit wet and dry paper, using a polished granite tile as a sanding block. That gets all the machining marks off, and makes it very flat (more flat than a machine can get it). It will allow for relative movement between head and block without harm to the gasket.

I am not familiar with permagasket aviation nor how it works, but I would be real wary of using anything on a head gasket. With the extra cooling holes, the very flat and near mirror smooth head and block, I have not failed a head gasket yet on my 11.25:1 compression ratio 3ac engine, despite a lot of abuse.

BTW, though it likely does not matter much at this point if you already did it, I would not add any more holes to the head gasket than just under the exhaust ports, as I show in my picture in the thread on the topic. when you add more holes you allow coolant to circulate into places where it was not intended, and that means possibly starving coolant from areas where extra coolant flow is needed. When you open one hole somewhere, that means less coolant flow somewhere else. So always do head gasket modifications very cautiously. More holes is not always better.




only add the extra holes, no larger than 0.25", where shown here (indicated by the point of the pencil), between the 1 and 2 cylinders, and between 3 and 4 (not between 2 and 3, that area is already cooler due to intake port locations) and only add them to one side of the head gasket, right under the exhaust port location.

[gatemaster]

permagasket aviation gasket sealer is a thick brown liquid sealer. I have never had a head gasket leak no matter how high performance an engine is, including my 396 aluminum head engine with 12 to 1 cr and 500+ hp, when using permagasket aviation sealer. I understand what you are saying about the different metals, I understand that completly. My point is that those type of head gaskets that slide do not work on this engine. They may work fine on an engine that has better design. So I compensated for both poor designs and I am not changing head gaskets, like others are. I did drill the holes at .25, maybe too many holes I don't remember but my engine runs like it should.