89 Toyota Supra Turbo

Engine Replacement

September 2002 - November 2002

The car was performing poorly in hot conditions. With no A/C load, on a flat road, the engine temperature was rising at a mere 2400 RPM, about 65 mph, in 105F ambient air temperature heat. The engine cooling was not functioning well, and led to a small but significant 2nd blown head gasket.

The radiator was replaced first, and then the car tested for overheating. The engine continued to overheat and lose coolant. The engine block was tested for a blown head gasket, and cooland registered positive on the test for a leak in the cooling system internally. A BHG was confirmed, small, but still causing coolant loss and overheating due to coolant loss.

The engine was pulled and the block inspected.

The engine block cooling passages were discovered to be filled with a large amount of scale, restricting flow of coolant.

Rear 3 cylinders


front 3 cylinders


Notice the blocked coolant passages on the engine. This was a used engine that was not opened up before. Proper coolant was run in the car since its installation in July 2001. Prior to that, the engine history was uncertain. It appeared from the condition of the block that the previous owner had run the engine with improper coolant (tap water). The cylinder wall sides were blue in several areas.

Another problem that was discovered was that the cam journals were badly scored, indicating that the engine had run with insufficient oil. Again the engine history was questionable. This was a painful and expensive lesson. I had worked with an inexperienced mechanic in Pasadena, California, and did not discover his inexperience until after the used engine was installed. It seems funny now, but it was not funny when I picked up the car from his shop and drove home to find the turbo boost gauge behaving erratically and the engine feeling very sluggish. I brought the car immediately back, whereupon he informed me that this was his first turbo installation, and he "was not a turbo expert". That explained also why he kept trying to convince me that sincethe timing was electronically controlled and was not adjustable on the engine!

I should have reported his shop to the Bureau of Automotive Repair, because it was clear he had poor mechanics working for him, and that he was incompetent as well. I was getting ready to move to a new city, so that was my excuse for not getting around to that. I did immediately take the car back home, troubleshoot the vacuum lines, and found that the EGR lines were reversed, the turbo actuator vacuuum lines were also reversed, and some vacuum leaks which I plugged or fixed. Of course the turbo gauge read correctly once all this was done. I set the timing myself, and discovered that two of the spark plug wires had been crossed as well!

The final leg on that engine was a trip I made to Bishop, California, about 230 miles north, of which 160 or so are through desert. The temperatures hit 108F and the engine overheated.

The replacement engine is a low mileage engine from Japan. I worked with a local mechanic in the city I live in now. Their shop found the engine from a reputable source they work with. The replacement engine was installed in November 2002 and has run very well ever since (so far it's January 2004).

The stock cooling system is in use again, all new.


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