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Gs400 Engine Re-Build


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Although you didn't say what problem your current engine has, my suggestion would be to look for a used engine from a salvage company and would speculate that buying a used engine would be far less expensive than having your current engine rebuilt by somebody else.

I've completely rebuilt engines and it is a tedious and time consuming job. I've also bought factory rebuilt engines (Mercedes) and they are a complete bargain compared to having a mechanic rebuild one or even doing it yourself if you factor in the cost of your time. If your car is not a daily driver, I suppose you could rebuild it yourself and farm out the difficult work to machine shops if you don't have the tools to do it yourself.

Used engines can be pretty cheap. Have you looked for one?

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Removing and installing an engine should be no more than ten hours labour, maybe less. That's a grand. Used engine a grand. That's it.

Keep in mind that no-one makes over-size pistons for these engines, not even Lexus. So a re-ring is all you'll get.

Just why is anyone advising a rebuild in the first place?

Seems to me someone is setting you up. That car in good condition isn't worth a whole bunch more than the estimate you got......

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Blowby at 80k miles? If the engine has been serviced properly it should be running like new. These are very long-lived engines.

Blowby is caused by stuck piston rings. If it was my car, I'd change the oil and use a high detergent/dispersant oil, like Exxon XD-3 diesel oil. It's a little heavy, 15W-40, but it will clean up the inside of the engine over time. Don't use any addtives of any kind. Just use a good quality diesel oil, which have more detergents than today's gasoline rated oils. Then drive the car for a while - maybe 5k miles - and see if the blowby is reduced. Change the oil several times at short intervals, say 2k miles. Use a good filter.

If the engine has to be changed, and I doubt it, then the shop doing the work should supply and install the engine. The trick is to find a competent shop, and you need not go to Lexus. Any shop specializing in Toyota could do the change.

But try changing the oil first and driving it around. It's a lot cheaper.

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SRK, my engine has 225,000 miles. The replacement engine the dealer found has 80,000. I will definitely try the diesel oil. I stopped taking it on the Interstate I only let my wife use it around town. And I put in a can of restore, and it doesn't leak at all. One question, the detergents will let the rings move on the piston freely? That will seal the cylinder and reduce or stop the blowby? I was assuming there was just a gap between cylinder wall and ring that couldn't be filled.

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If the rings get carboned up they no longer produce enough pressure against the cylinder wall. Oil changes can free up the rings by removing the carbon, although it's a slow process.

With 225k miles if the engine has not been looked after it may not respond.

So how much oil does the engine consume between oil changes? You've said it doesn't leak. Oil consumption is the first and most important measure.

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1990LS400, what would you suggest? Should I try someone besides the dealership? Can a regular shop do the engine swap? They wouldn't need proprietary Lexus diagnostic computers to tune etc.? Because the dealership isn't buying off of ebay, nor will they let me and bring it in.

Yes, a "regular shop" can swap an engine. No, "proprietary Lexus diagnostic computers" are not needed - any good repair shop has everything needed.

If your GS is at 225,000 miles and really does need an engine transplant consider selling the car for salvage or parting it out yourself.

I was told early last year that my 2000 LS400 at 135,000 miles had an insurance value of about $15,000 (due to its exceptional condition) although it's market price here in the midwest is probably no more than $7,500. If my engine was "blown", I woudn't for a minute consider replacing it - the car would be sold to a salvage company or to one of my mechanic friends who would replace the engine at his leisure.

If you don't depend on the car, you could swap the engine yourself. I did things like in my younger days (and completely torn down and rebuilt engines) and it is not brain surgery. But don't do this unless you consider it a fun hobby.

I'm interested in answers to SRK's questions ... e.g. how much engine consumption is going on. These V8 engines can last to extraordinarily high mileages --- far longer than a mere 225,000 miles.

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I would say only a little oil loss. I change it about every 10,000 miles; I don;t specifically remember adding any in-between, so it must not have been significant. It has been leaking for a good 8 months, and any oil I added was minimal. That being said, only within the last 2 months did I have both valve cover gaskets and front and rear seals replaced. The dealership would keep saying it's the valve covers, then the rear seal. When we replaced all and it was still leaking they discovered it was blowby. I knew before they did that something was wrong, because about in 2008 I had the valve cover gaskets replaced. So it struck me as odd that they were leaking again.

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It sounds like you are getting "hosed" by your Lexus dealer. Are they any indie mechanics nearby that are knowledgeable on Lexus cars?

Have you had a compression test? If you haven't I would suggest having somebody besides the dealer do it. Or you could buy a compression gauge and do it yourself - makes me wonder where my compression gauge and remote starter switch are ... haven't seen them for 20+ years but I know they are in a box someplace. My remote starter switch is a little like this one except mine can be foot operated: http://www.summitrac...rts/ANM-CP7853/

I can't tell you how many times a service writer at a car dealership service writer has tried to sell me unneeded repairs or I had to intervene on behalf of friends and relatives. One of my "favorites" was just after my basic warranty expired on my first Lexus - a 1990 LS400. My car had suddenly developed an intermittent starting problem and the Lexus service writer told me I needed a new main ECU - $1,000+ in about 1995. When I asked to use their his phone to call a tow truck to take my car to an indie shop for a 2nd opinion, the repair suddenly changed to replacing a defective battery cable for which I think they charged me only $15. I've never seen a service writer "dance" so nicely! That Lexus dealership was and still is Superior Lexus of Kansas City. It pays to have a little automotive knowledge and be willing to get second and even third opinions.

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1990LS400,

The dealer says they did compression test. I am going Friday to have a local shop do another one so I can get specific data. What makes you say I am getting hosed. Oil is leaking from PCV valve on drivers side valve cover and from vent on passenger valve cover.

SRK,

Having heard all of the info. do you still think I need to run the diesel oil? I was going to try it today.

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Apparently the symptoms are that it leaks oil. You stated that it doesn't burn much oil, or lose it between changes. You don't mention the compression numbers, but I'm assuming they are OK. And the cure according to the dealer is an engine rebuild. That makes no sense.

Yes, change the oil, using diesel engine oil if you wish, or any good quality oil. But change it more frequently.

Unless you have more information, a leaky valve cover is no reason to rebuild the engine.

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No, the dealership says compression is bad. But when I went back about 2 weeks later, they say they don't have specific psi numbers or how many cylinders were low. They didn't save any of that. The valve covers are leaking even with new gaskets (from the vent and pcv valve). What other info. should I get for you to help? I will let you know specific data after the compression test friday, but let me know of any other data I should try to get while I have it at the shop. I mean we are tallking about a dribble coming out both covers, so I don't think the current state would mean adding alot of oil in-between changes. The reason I don't just ignore it and keep driving is, I have replaced two alternators due to these oil leaks shorting them out. Also, I have noticed alot of soot on the back bumper/trunk. And I keep thinking I smell gas in the exhaust fumes.

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So the dealer wants you to rebuild the engine but can't supply data to support that decision? That's why Jim and I don't trust your local dealer.

What you describe sounds like a low cylinder or two. Of course they might all be a bit low if the rings are stuck, and if so, they're carboned up from lack of oil changes. But you state that the engine doesn't burn oil. Yet the cats are spewing soot and smell of gas. It seems there is a problem.

Change the oil to a diesel rated 15W-40, and do so again after 2000 miles. See if the engine improves. If not then perhaps it is time for re-ring.

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SRK,

I said I have not been taking the car on the Interstate (to reduce) the oil leaking. I just let my wife use it around town. I drive round trip 160 miles a day to work. Do you think I should take it to work (Interstate travel) while it has the diesel in it? Or should I continue to just use it around town while the diesel works on the pistons?

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Highway driving will certainly fling the oil up into the rings faster, although the engine may burn a bit more. But 15W-40 is heavier than what you are using now, so it should be fine.

Drive it and see - you won't hurt it.

Good luck!

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Well, it sounds as if you two gentlemen's instincts were correct. The second mechanic said I got completely robbed. He said all 8 cylinders have between 120 and 130 psi which in his opinion is normal for 220K miles. He says the dealership never replaced the valve cover gaskets and that is all I need to replace. He also believes they never replaced the rear seal, since the exhaust bolts are rusted and don't show any signs of recently being un-bolted. I am in contact with the owner of the dealership to get my money back. We will see how that goes (but my sister is an attorney).

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Let's not celebrate until after the valve cover gaskets and rear seal are replaced. The compression figures are low but that could be related to the testing method; it's more important that they are consistent.

Let us know how it turns out.

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Now I'm really confused. I went to the dealership and we tested the cylinders. Their gauge shows 80-90 psi on cylinders. So I saw no need to have them pull off the valve covers. I don't know how one mechanic shows 120-130 and another shows 80-90. The dealership said the only thing they could think of was the cylinders were not dry when he tested compression.

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