billymild

My car has seemed to run just fine since I bought it, but lately I have been concerned it may have a blown headgasket.

After my timing belt/water pump service I noticed the coolant was a little low. I added some coolant up to the high mark and drove it. I didn't really watch it, but occasionally at gas fill ups I would check it. It appeared to be a little on the low side again. So I added more coolant. My buddy who is a Lexus/Toyota Mechanic said sometimes the 4.0 liter engine takes a while to get any air pockets out and that could be what caused the low coolant level. My car doesn't overheat, doesn't really idle "rough", or anything like that. I notice no fluids on the ground either.

My question is could I have a headgasket issue. My car has 144,000 miles on it. The coolant looks pink still and clean. The oil does not show any symptoms of milkshake either. Am I just paranoid or should the dropping coolant level be a sign of an issue?

I also just noticed after getting a car wash, with my engine just shutoff the tailpipes let out a little steam/smoke.

LScowboyLS

headgasket issues are essentially unheard of on LS400, so forget that

you have air in the system - make sure the thermostat is "clocked" with the jiggler hole in the 12'oclock position, and make sure that coolant was added at the fill bolt (large downward facing bolt behind thermostat housing) and then burp the large hoses while filling with heater on max

then, over the next days, the system will self-bleed via repeated hot/cold cycles, and you can just top it up in the overflow container, and eventually it will no longer drop as all of the air works itself out.

timmy0tool

iTrader: (7)

agreed with cowboy, and your friend too. the V8 does take awhile to get the air out of the system so keep topping off until it stops being low. seeing a low coolant level is completely normal directly after a water pump replacement. it just needs to be monitored and added as necessary.

these motors run well over 300k if maintained properly so you need not worry! even those who are not as religious in their maintenance still see over 200k, a testament to the build quality!

Mythotical

Just an FYI. Some after market thermostats have no burp hole. No need to worry though, you can still pull the fill plug and do the manual hose squeeze thing. I however will always use a genuine thermostat.

tjschraf

After reading this I had to double check and make sure it wasn't my initial post. I have in between 142-144 on my 1995 and have been sucking down coolant but not visibly leaking. I am pretty sure it's a hose or something and not a huge concern to me at the moment. I just need to last the winter. Once i found out head gaskets are pretty rare, I decided to keep pouring more in at least until it gets warm.

The worst part for me was having no coolant and no heat in - weather.

I fill it every couple weeks with toyota red and sit back and admire the fact it is 20 years old and drinks a bit of coolant. I was a 5 when this car was built and over the years I have had far more issues than it.

LScowboyLS

taking the plastic undershield off for a few weeks can make finding leaks so much easier!

if it is "drinking coolant", then the coolant is going somewhere, either on the ground or out the tailpipe, or in the floorboard (heater core) and if it was burning that much coolant out the tailpipe, your car would look like a smoke bomb going down the road (white smoke)

RA40

iTrader: (6)

In addition to what has been mentioned, one of the subtle place coolant can be lost is the radiator drain **** O-ring. Since it drains out the tube, you would not see this when the car shuts off and there is no system pressure.

MattLS400

please explain the "clocked" with the jiggler hole in the 12' o clock position

timmy0tool

iTrader: (7)

the OEM thermostat has a little hole with a jiggle pin on one edge. that hole needs to be at the 12 o'clock position. in other words, at the highest point so the air bubbles can pass through and work themselves out.

pic in this thread.
https://www.clublexus.com/forums/ls4...gle-valve.html

MattLS400

please see attached pic

LScowboyLS

I see no jiggle valve on that thermostat, perhaps because it's not the OEM Kuzeh thermostat that me, Yamae, timmy0tool, and others have recommended.

don't cheap out on this critical part, it is only $15.82 at Sewell Lexus!

MattLS400

Ok i saw the Jiggler hole...its on the other side which is not seen in the pic.....but guys, after installing my thermostat, then bolting back the 2 knots and re-filling....i noticed it was leaking from the underneath of the black thermostat housing....however, when i removed the thermostat it installed fine with no leaks after.....i was wondering, should i put back the thermostat and use silicone to prevent any leaks ?

Kram

never use silicone and orings together just clean the surfaces and make sure the thermostat fits into the manifold and if you do not replace the oring which has to be purchased separate you will set yourself up for leaks, and never think that over tightening the bolts will stop the leaks all it will do is damage the housing,also there is only 1 lb pressure on the cap and it may be alowing fliude to push out of the radiator holding tank. Purchase a new cap.