Overheating Puzzle
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Lifetime Rennlist
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The overheating at idle and cooling with the engine rev'd probably points away from a headgasket failure. Generally, headgasket problems multiply as load increases. My nickel (devaluated to too sense thanks to US economic policies...) says that the water pump is a key part of the problem.
Back now. Good news, Success!

So here's what I did. Oh and I digress for a moment. There is no "bridge" or cross-over at the rear of the block as I had implied in my previous post.
At the back of the head on the driver side, there is a cover over what would be an outlet for the heater valve on a RHD. Both heads have them and the US cars have the heater valve obviously located on the passenger side. I looked at the proximity of this access compared to the drain plug and it is virtually located right above.
I put the old WP back on just to plug that hole, put the drain plug back in the passenger side and filled with smokin' hot water. BTW, I had removed the T-stat so I knew I was full if water spilled through the overflow at the bridge.
ADDED: Forgot to mention that I stuck a longer piece of tubing down the access attached to the compressed air and zapped it several times. I worked it down as far as I could hoping to get into something that would get stirred/loosened up from the air.
I then started using a plastic zip-tie as it was flexible enough to make the turn in the drain plug. All I kept getting was what looked like wet mud at the tip of it. I then got out the coat hanger and did some bending. Worked it in there and the next thing ya know, I was getting a dribble. I kept working it until finally the dam broke. I got another bucket of scorching hot water and filled again, but this time, I used the fitting I had made with the compressed air hooked up. Filled again and hit it with several hard pops of air and some steady ones. Removed the fitting and drained. Then drained the other side again.
Not sure whether there was one thing that did the trick or all combined, but I'm a happy ****!!!
I will have a new WP and other items tomorrow to get it all back together. Incidentally, I even put the T-Stat in boiling water tonight to make sure it works...which it does quite well.
Once I get everything back together, I will most definitely do a serious system flush. Thanks for the advice on that.

Note the pics below and the crud that came out of the block. I think there was calcium, rust, a gummy bear and possibly a couple of Smurfs, but i can't really say for sure.

Thanks for the support everyone. I can only hope that my request for help on these things helps others as well, now and later.





Last edited by 928ntslow; Jan 18, 2008 at 04:15 AM.
well done on getting the coolant flowing out of the drain holes; do not remember all the posts but I assume you will give the new radiator a good & seperate flushing before you button everything back together??
Marton
The Best Porsche Posts for Porsche Enthusiasts

Sounds like you cured your issues..good deal...
later,
Tom
89GT
82 Track Car in progess
All the crud around the drain plugs are an indication of other junk in low spots throughout the engine or heater core plumbing. I would still backflush with or without cleaners to clear out any remaining debris.
Dennis
Based on the info in your post, he said the car probably sat for a long time (several years) and coolant was not changed for several years. When coolant is not changed out for several years, the stabilizers that bond the water and glycol together break down. What happens next is the glycol and water separate. The glycol turns to a jelly-like consistency and sinks to low lying areas in the cooling system and the water "floats" on top of it. That's why the water pump impeller has rust on it and any other metals in the cooling system would have rusted too (metal y-pipe on the passenger side fender well?).
Before using a detergent or flushing solution, put some of the "fish eggs" and hot water in a jar with a lid and shake it up. If the "fish eggs" dissolve, then a detergent/flushing solution is not neessary. Install a new water pump, fill the cooling system with water, run up the temp and drain. Repeat several times.
Also, check for a head gasket leak as the cylinder heads are made of A356 alloy which is softer than the block (A390 high silicon alloy). I would not be surprised if the cylinder heads/gaskets are corroded.
Adam
Rennlist Member

Since I brought up the "green coolant = bad juju" comment I guess i should explain myself.
I didn't realize that the coolant in this car was fresh, so I appologize for jumping to conclusions. However, as recently as 2-years ago, the green coolant being sold at my local auto parts store was not phosphate-free. There may have been brands available that were green and phosphate-free, but my store didn't have it.
However, when I was recently there to pick up some coolant for my rebuild, I noticed that all of the name-brand green coolants specifically said "Safe for All Engines" and when I looked at the ingredient list, I did not see any mention of phosphates in their chemistry. I did not look at the house brand.
That said, I decided to stick with the DexCool. Mark it up to personal preference, I guess.
So to sum it up, I agree as long as the coolant is phosphate-free, it should be good for our cars regardless of the color. However if your coolant is more than a couple years old and is green, you should seriously think about changing it before it potentially eats your heads.
as recently as 2-years ago, the green coolant being sold at my local auto parts store was not phosphate-free.
Luckily I am partly colour blind so I always have to read the small print on the label.
Marton

