the exhaust gas sniffer in the coolant overflow tank is the test to make sure and do!

the other definitive test is compressed air into each cylinder (you need an adapter for your air compressor, very inexpensive)

I still doubt you have a blown head gasket, as those are so rare on an LS400, but please taste (not kidding) the drips from the tail pipe, coolant tastes sweet like sugar water!

 

Exhaust sniffer is a great idea! It's one of the things I am going to be sure to do. I will buy a Napa block tester (or rent from Auto-Zone if they offer it?) and see what it says.

As far as tasting the coolant, I would agree with you but in this case I completely drained all the old neon green (not factory toyota) coolant and replaced with distilled water because my original plans were to flush the coolant out then replace with the Toyota red stuff.

So all I will be tasting is distilled water mixed with exhaust gas...

The compressed air into each cylinder is the leak down test that I will absolutely be sure to do along with the compression test.

I'm dying for the answer, so I cant wait until I get the time to rent the tools and do the test.


I am leaning towards no blown gasket also due to the fact that it still runs baby bottom smooth and as quiet as a sleeping baby (with the exception of maybe an exhaust leak).... but that doesn't always mean anything. The tests will hopefully tell me whats going on.

 

the compression test is pretty much obsoleted by the much more revealing compressed air test, but get that exhaust gas sniffer rented or borrowed, that is the key one! - and replace some of the water with coolant, even the green stuff is fine for a short time, since you are going to flush it anyway, and do the taste test!

 

Actually all new coolant sold now has Bitrex in it. So it will be bittersweet.

 

any distinct taste will tell us this is coolant and not just condensation, which would be a big breakthrough in diagnosing it!

 

So I have damn good news. I ran the car a whole bunch this week and the steaming completely stopped!

Just for good measure, and my own sanity, I decided to go ahead and do the compression test today. I also used the exhaust gas sniffer (block checker) tool today. I rented it all for free from auto zone. I'm pretty happy to say that everything passed.

The block checker didn't detect ANY exhaust gas AT ALL in my cooling system. I let the car warm up and even revved the engine up a bit and did the sniffer test for a few minutes and got NO color change in the detector chemical fluid.

I was even more happy after I did the compression test and saw that all my numbers are matching up pretty good!

Here were my results:

Dry Test:
Piston # 1 = 154
Piston # 2 = 160
Piston # 3 = 160
Piston # 4 = 160
Piston # 5 = 160
Piston # 6 = 160
Piston # 7 = 162
Piston # 8 = 157




I guess cylinder number 1 was somewhat low, but it was WELL withing 14PSI of the highest reading and to be honest could be due to the fact that my partner probably didn't crank the engine for EXACTLY 5sec the first time.

So now I know that my engine is in unbelievably excellent condition, and I couldn't be happier.


I didn't even bother with a wet test because the dry test was so great... and of course, there was no need for a leak down test on a car with no leaks.

Thank you for everyone help.

(by the way, this is apparently NOT the first time someone changed a timing belt and had the engine smoke.... it happened HERE. So if this ever happens again to anyone, don't jump the gun like I did. The fact that it was a new to me car was what mainly had me concerned. )

I did taste the fluid earlier in the week after I read your post and it only tasted like straight up water and exhaust.

Now I just need to get back out there and fix my exhaust leak and see if the CEL comes back on after fixing.

 

Good news and congratulations...took a little work, but now you have great peace of mind...