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Discussion Starter · #1 ·
I just purchased (within 1 week) a 88 626 GT. The owner (a local mechanic) said the engine has been completely rebuilt by him and should have less than 1k on it. About 4 days ago I filled the coolant tank to the top (It was completely empty) and today I discover it is completely empty again. And I mean BONE DRY. Also, the valves and rockers are noticably audiable. One week ago the engine purred like it was brand new (It almost was). Sitting at a stop light on my way home after I discovered the valve/rocker noise and lack of coolant I notice a small amout of lightish gray smoke comming from the edges of the hood. Being concerned I babied it home and popped the hood. Sitting at idle the noise level of the valves distubed me. Also sitting at idle there didn't seem to be any visible smoke. Twisting the throttle slightly revealed small amounts of smoke comming from the underside (I think) around the header/turbo area. After a few more twists to try to pinpoint (unsuccessfully) its location I closed the hood and to my astonishment I saw large amounts of grayish smoke flooding the street. So I popped the hood once again to see what the coolant level was at and it appears (APPEARS) that it has already dropped 1/2 - 1 inch. I then removed my oil filled cap and smoke began to pour out from my valve cover for about 1-2 minutes until I walked away. I also noticed what sounded like boiling water or somthing of the nature comming from the header/turbo area. Any Ideas?
 

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Discussion Starter · #2 ·
I have roughly pin pointed the location of the smoke comming from the engine bay. It seems to be comming from underneath the heat sheild covering the headers. When I start my car (always takes a few seconds) everything appears normal (except the valve noise) but if i rev it to 4k in N a few times smoke begins to pour from the exhaust and from underneath the heat sheild. I might have found the solution to why the coolant tank keeps draining. I opened my radiator top and noticed that it was extremely low. Right now I am waiting for the engine to cool down (I filled it up and ran it abit) to recheck it.
 

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Your problem isn't as big as you might have feared.
The smoke you are seeing is just steam. What happened is one of the turbo's coolant lines has busted, and the coolant is spraying out all over the turbo and vaporising, making that big cloud. Use the Mazda part to replace this hose. Fill it up with coolant again, and don't drive it until you are going to go directly to the mechanic.

Valvetrain noise is common on these cars but it shouldn't be super loud. Some people have good results with Marvel Mystery Oil to eliminate the valvetrain clicking. These cars have hydraulic lash adjusters and they get clogged with gunk after awhile (did the previous owner re-use the head?). Make sure it has oil and isn't loosing it somewhere.
 

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Yes, I second that; get that turbo coolant hose replaced right away, else you will cook the engine. Do not drive it unless replaced or on the way to the shop with LOTS of extra water. Do NOT use the turbo or take it up where the turbo spools.
 

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Discussion Starter · #5 ·
That soulds like it could be it. I a taking it in tomorrow morning. I'll make sure to keep it below 2k. Also someone else suggested the MM oil so I think I'll try that. My Mx6 has a bad valve and rocker which is causing the noise on that car so I was wondering if I had the same problem. Thanks guys.
 

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Yes while your at the dealer getting that hose, pick up at least one HLA, when I got my 88 626 GT had the same problem. It turned out that I had 2 HLAs collapsed, one on the exhaust side and one on the intake side, replaced them myself and now the engine is silent as new. Pretty satisfying for about $40 and an hour of work.
 
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