1995 Ls400 Exhaust Leaking, 1991 Ls400 Seeping Coolant

[jqzhang]

Hi,

Hope you all is well.

But bad luck for me. The 1995 one has a broken exhaust, probably EGR pipe but not sure since it's hard to detect. Any suggestions?

For the 1991 LS400, coolant is leaking slightly from the bottom of crankshaft pulley. I am afraid the water pump is gone. Any someone confirm that? Because I don't want to go through the pain of replacing water pump, probably timing belt too, but end up with something that doesn't take me that far.

I have a used part of water pump taken out from a 95 SC400, which can probably fit my LS400 of 91. If not, have to get a new one.

Greatly appreciate it!

jqz.

[curiousB]

The leaking coolant is a sure sign of a waterpump failure. I wouldn't leave this too long as the bearing in the pump can eventually seize and snap the timing belt. I don't believe your engine is an interference type but it will still be an inconvenience.

The cost of a pump isn't outrageous ($69.00) so I wouldn't even consider a used one.

http://www.store.partsdinosaur.com/product1884.html

I'd put in a new timing belt while I was at it.

http://www.store.partsdinosaur.com/product1888.html

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As for detecting a leak get a length of 3/8" hose and hold one end a inch or two so away from your ear and then move the other end around where you think the leak is. You'd be surprised how accurate this is for pinpointing a sound.

[jqzhang]

Thanks for the quick return, and the tips too. They are going to be helpful.

I did not know so many Toyota and Lexus models use the same water pump. Good to know.

I read some posts saying that if the the leak is at the EGR pipe, the upper end of the pipe can be blocked or capped. The emission won't be affected so the car can still pass inspection no problem. Sounds hard to believe. What if the CheckEngine light might come on because the oxygen sensors might sense the change first. What would you think?

Thanks again.

[curiousB]

There is plenty of history with this egr pipe cracking. Search the forum here to find more. I would use the 3/8" hose trick I mentioned earlier to pinpoint the problem before ripping things apart. There is a section of the pipe that is corrugated and it tends to crack on one of those seams. Its a bit tricky to replace but you'll find instructions here on how to do it.

I would resist making changes such as; capping off, eliminating, rerouting, and so on. These components work in a complex closed loop system and while you think you are fixing one thing you might actually break something else. I learned this lesson last year when I had a faulty catalytic converter DTC and CEL issue. After a few weeks of checking and swapping out gaskets, an O2 sensor and a catalytic converter the problem persisted. In the end it was a cracked pipe a few inches after the second O2 sensor. All I needed was some welding. So be careful about closed loop system diagnosis. Its not always what you think.

Emission inspection of cars where I live is simply a computer connection via the OBDII connector to check for trouble codes (DTCs). If the CEL is not lit you will pass in IL. They don't use a probe in the exhaust pipe. Is your CEL lit?

[jqzhang]

No, my CEL is not lit yet since I stoppd driving the car after I heard the noise. If I kept driving, it would light up for sure.

I agree with you about the re-routing stuff because you cannot beat the design of the car.

I have a 96 Lancruiser too. There is slightly leaking in both converters because of rust. I tried welding using flux core wire (MIG welding machine). It is not working well: either burning the steel through or not enough penetration. Someone suggested using gas welding. I'm not sure. Any ideas about that? Of course, for the EGR pipe, I'd probably replace it with a new pipe.

Thanks in advance.

[landar]

It might be worth taking your car to a competent exhaust shop where they can put it up on a lift and look over the situation. They usually know what can and cannot be welded back together and how to do it. Even if you do not have it repaired there, they might do a quick inspection and estimate of cost for free or a small charge. Then you go from there. Nothing like having another set of close-up eyeballs and ears on the problem, something we cannot do from cyberspace.

[jqzhang]

Yes. It makes sense. I'll probably do it during the holidays.

One more question for the 1990 one: the one with water pump problem. I am in the process of ripping it apart but one thing surprised me. The timing belt looks quite new. It must be replaced not too long ago (but not me). I guess they changed the belt not the water pump. My question is, can I replace the pump and leave the belt alone? It looks like I have to loose the belt before I have access to the pump.

Thanks again.

[landar]

Well, for one thing, you cannot really determine the age or condition of the belt just by looking. Many have reported that even at 90k miles, their timing belt looked good. You could reuse the belt but personally, I would caution against it. The belt is only about $60 new and would be well worth the added cost. And yes, the belt has to come off to gain access to the pump. Once you get things torn down to that level you will see that the backside(smooth side) of the belt is actually driving the pump. You really should replace the pump, belt, tensioner and two pulleys while you are in there. I would also recommend a new front crank seal and perhaps cam seals as well. Those seals could be left as is if you first determine that they are 'dry' (no oil seeping).

There is a tutorial on the 90-94 timing belt water pump replacement that you might find helpful. It is a fairly involved job with lots of labor. That is why I recommend all new parts. You do not want to do this again anytime soon. Heres the 'toot' -> http://www.lexls.com/tutorials/engine/timingbelt.html

[jqzhang]

I understand what you're saying and I agree. Now I'm going to the full length to have it done, taking your advice. I did have the link that you sent me, which is my guide for the project. I also have the detailed description from TIS (Tech. Information System) so I should be OK.

Thank you very much for all your help.