8 cylinder front engine iconic vehicle
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By jschiller
#144694
I am well aware of the issues surrounding the head cancer problem but I have a question about it. Is there a way, short of removing the heads, that you could determine if you have a problem currently? I know its just a matter of time before you need to address the issue but the question is starting to concern me now.

I have an 89 5sp and my issue is I'm losing coolant but with no external leaks or coolant smell in the car, no white smoke but a slight temp gauge increase after about an hours city driving which I attribute to the loss of coolant. Fans are working correctly, I had the controller and Final Stage rebuilt. I did replace the coolant cap which helped but I still lose about 1 inch of coolant in the tank after a drive. Do the exhaust gas coolant testers effectively assist in diagnosing small coolant leaks that would result from disintegrating head gaskets ?

My compression is good, the engine is strong but the heads have never been off in 160k miles. What should I look for here? I have a timing belt/water pump job coming up soon so the car will be out of action for a while and I might address the issue then, depending on the advise I get. Thanks.
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By h2pmr
#144712
IF the head gaskets are original and the coolant has not been changed every 2yrs from when it was new, the head gaskets will need replacing.
IF you are also having to top up the coolant with no visible leak, the head gaskets need replacing ASAP
the only way to know how bad the heads have corroded is to remove them.

one of my head gaskets had disintegrated that much that the water drain on that side of the block was fully blocked and the water only dripped out when i removed the drain plug.

ask Roger for a list of parts you will need, sooner rather than late in my humble opinion

cheers
Phil
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By jschiller
#144715
That's kinda what I am thinking as well. I have a well documented list of service done to the car starting in 2004 and there is only one mention of a coolant flush in 2013 and no head work at all. So besides the head gaskets, I'm probably looking at chain tensioners for sure plus whatever I find when I get in there. Ah well, its only money :puking:

Thanks for the input!
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By worf
#144745
Phil's provided a pretty good summary.

Short answer: in the absence of a medical grade endoscope you can't inspect anything. Even with that, you'd only be able to inspect the gaskets. You would not be able to inspect the deck surface of the heads.

Head gasket death and head deck cancer are silent killers. It is very safe to assume that your gaskets have - or are working on - holes. When the gaskets get "holey" the holes short circuit water circulation. For example if you get a hole in the gasket between #3 and #4 cylinders or #7 and #8 then the #4 or #8 will not get as much coolant flow around the cylinder and head. This will cause the effected cylinders to run hot. This will not be evident from your coolant temp gauge since it measures temperature at the water bridge.

What is unknown and unknowable until you've soda blasted the heads is the extent of any "cancer."

Either or both of these problems have a minimum expense to correct (i.e. the expense of pulling the heads.) But as the problem(s) are allowed to persist the expense goes up. For instance the longer head corrosion is allowed to continue the more expense is involved in welding the heads. At the limit, if a compromised gasket or deck surface allows a cylinder to hydro-lock you have a cracked cylinder which then becomes rather more expensive to correct.

jschiller wrote: Mon Apr 11, 2022 12:56 pm I have an 89 5sp and my issue is I'm losing coolant but with no external leaks or coolant smell in the car, no white smoke
This -^ issue and ...

jschiller wrote: Mon Apr 11, 2022 12:56 pm but a slight temp gauge increase after about an hours city driving which I attribute to the loss of coolant.
... this ^ may be separate issues. A slight loss of coolant doesn't necessarily lead to higher operating temperature.

What is very common is a leak in the "vapor" part of cooling system. A coolant vapor leak may actually increase in severity with a new reservoir cap. Vapor leaks are a minor PITA to find.

The vapor part of the system starts at the two little hoses that attach to the forward-facing side of the reservoir. Those hoses, every connection, clamp, etc., is a possible vapor leak. The vestigial over-pressure switch between the reservoir and washer filler neck is a very common vapor leak culprit. Deterioration of reservoir at the seam for the body and the cap is also common.

The best way I've devised to find those leaks is to use a coolant system pressure tester, a "bottle of soap bubbles", inspection mirror, your eyes, and your ears.

Theoretically, poor system pressure due to a vapor leak might result in elevated temperature. In Florida? Maybe so. The coolant pressure tester would enable you to determine the operating pressure when the engine running.

The temp gauge increase may, or may not, be diagnostic. Might be the sender. Might be wiring. It may be real in which case water pump efficiency is the first thing to consider. If you have a metal impeller water pump (and it isn't a Gaurdian Pump) then you can check the pulley for into-block migration (a borescope is handy for this, but it can be done with a very small inspection mirror and LED snake light.)

jschiller wrote: Mon Apr 11, 2022 12:56 pm I did replace the coolant cap which helped but I still lose about 1 inch of coolant in the tank after a drive.
Typical for a vapor leak.

jschiller wrote: Mon Apr 11, 2022 12:56 pm Do the exhaust gas coolant testers effectively assist in diagnosing small coolant leaks that would result from disintegrating head gaskets ?
They can tell you if you have a leak. But, a negative result does NOT mean that you DON'T have a leak.

jschiller wrote: Mon Apr 11, 2022 12:56 pm I have a timing belt/water pump job coming up soon so the car will be out of action for a while and I might address the issue then, depending on the advise I get. Thanks.

I tell folks that if you've got a tb/wp coming up, and if your oil pan isn't dry, and if your intake and cam covers are in need, then it's time to pull the motor and do it all right. Takes less time. But, the WYAIT slope is steeper. The bottom of the slope is a stroker motor. :banghead:

Getting the heads off is all the labor of removing the cam covers, intake, water bridge, along with (at least) 1/2 of a timing belt job AND then removing the cams and heads.

If you're doing the water pump too... and if you have a cork oil pan gasket... pull the motor. Do all that stuff on a stand.
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