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Cracked Head Gasket Lexus SC300

Yesterday I was driving to work and when I came to a stop light my 1996 Lexus SC300 started experiencing a seriously rough idle. I also had a lack of power and rough acceleration through 1st and 2nd gear. Then the dreaded check engine light came on. My mechanic says I must have a cracked head gasket which is leaking anifreeze into cylinder #6, which caused the cyliner to misfire when the spark plug got wet with antifreeze. He said that there is nothing that can be done to fix the problem. I am determined to fix it since the car only has 85,000 miles on it. What can I do?

Well, you can replace the gasket, of course. Or are you wanting something in a bottle to dump in? That won’t work.

“My mechanic says I must have a cracked head gasket which is leaking anifreeze into cylinder #6, which caused the cyliner to misfire when the spark plug got wet with antifreeze”

If he came to that conclusion after testing (compression, leak-down, presence of combustion products in coolant, presence of coolant in motor oil…), then there is no likely alternative to head gasket replacement. However, the wording in your post–“must have”–makes me wonder whether this mechanic is doing an impersonation of Karnak The Magnificent and is just guessing as to the cause.

Ask him for a list of which tests he did in order to come to this conclusion, and request the specific findings of each test that he did. If he tells you that he “knows” that you have a bad head gasket without having done any tests, RUN from his shop and have your car towed to another mechanic who actually performs diagnostic tests before giving you a “big ticket” diagnosis.

I’m with VDC. What diagnosis did he perform to determine that you “must have a cracked head gasket”?

I’m also suspicious of his guess because he said nothing can be done to fix he problem. That alone makes me suggest you try another shop, unless what he really said was that he’d determined (after diagnosis) a bad headgasket and that HE could not fix it. Lots of good shops exist that prefer to specialize in repairs that do not include pulling the heads. They don’t want to get into engine rebuilds, subbing out head machining, or other types of more intense work. A blown headgasket, if you truely have one, is repairable.

If you check the toyota forums www.Toyotanation.com you will find that the straight six engine in the Cressida and he Lexus have a high rate of warpage failure between 90 and 100K…Many can be salvaged with planing the head and regasketing, but sometimes a long piece of aluminum like this is beyond repair. On the positive side, it shouldn’t be too hard to get a replacement (used, not new) from a car in salvage for reason other than engine failure. A cylinder compression test, review of plug conditions, coolant leakdown test and hydrocarbon test of coolant will give you the real answer. with out any more guess work.