Lsportline43

Well I believe the headgasket on my 1997 LS400 is seeping. All the signs are there. The coolant temp. gauge is slightly fluctuating, the coolant level is slowly decreasing, and there's a white smoke coming out of the tailpipe when revving the motor. (that's when the motor has fully warmed up)

So what are my options? I'm thinking a used motor, if I can find a cheap low mileage 1UZ-FE. Or should I just replace the headgasket on my current 1UZ-FE and change out all the gaskets while I'm in there?

The car has not overheated, but I'm not sure how much longer the headgasket will stay together.

LiCelsior

iTrader: (32)

hows ur oil looking like?

7schulz

I would have to imagine a HG would be cheeper then removal and purchase and instalation of new motor. Unless you have Edit: With 238K you might want a new motor thats your call.

jeffls400

My advice would be to have an oil analysis performed and / or a cylinder leakdown test done. Both are reasonably inexpensive and would probably provide the level of diagnosis you are looking for; they may also give some insight on the overall condition of the engine, at least from a relative standpoint.

Jeff

willhickey

iTrader: (1)

compression test do it yourself it will cost around 70 for the test...., and check the oil like the others have said and also check the coolant .. good luck hope it isnt bhg

Lsportline43

It doesn't seem as if the oil is mixing with the coolant at this point. I will likely get a compression test on the cylinders in the coming week.

And yes the coolant level has gone down slightly since I had the radiator replaced. New toyota red coolant was added and the level was right at the low level. After a month of driving the coolant level is noticeably below the low marker. And no, the radiator was not replaced because it overheated. The radiator just looked like it was going to go out, so I had it replaced.

I believe the car would be overheating by now, but the reason it isn't is because of the design of the cooling system. From what I understand the coolant reservior tank is mounted high in the engine bay, so that it will bubble air out naturally. My theory is that the cylinders are pulling coolant in and burning it off in the exhaust. Also air is getting into the cooling system, but is automatically bleed out.

Thermactor

iTrader: (1)

how can you be sure that the white smoke isn't caused by a faulty PS idle up valve?

get a block test done, they sell the block testers at napa, they go into the coolant neck and look for combustion gases.

LiCelsior

iTrader: (32)

your overflow tank is probably leaking. my coolant level decreases also but the leak is coming from my overflow tank.

Lsportline43

I hope my overflow tank is leaking and it's not the headgasket... but the only thing that gets me is that the temp gauge is fluctuating. We'll see soon.

And yes I think it could be the PS idle up valve, but how would that be diagnosised?

python

iTrader: (4)

a blown head gasket with coolant dumping out of the exhaust would ruin ur 02 sensors,cause the check engine light to go on and dump fuel into the cylinders and wash them out, ur plugs would be saturated as well....its not a head gasket. especially if u didnt over heat it to an extreme

Sixdown

I have the exact same issues on my car; fluctuating temperature gauge, missing coolant, and slight smoke on startup. I doubt it's my headgasket though and suspect my cooling system needs a good rebuild, although the headgasket is still a possibility with this many miles on my car.

Thermactor

iTrader: (1)

Just block the PS valve off with vacuum hose nipples from the car parts store. Put one nipple on the plenum, one on the black plastic resonator pipe, and two on the valve itself. Voila, problem isolated. I run my car this way anyway, and my PS valve isn't even leaking. Why play with fire if you don't have to?

Fluctuating temp gauge would point to the thermostat and air pockets. Change the thermostat and get the air out.

If you had a blown head gasket your temperature gauge should generally shoot right up to boiling and stay there.

Och

iTrader: (3)

Your headgasket is not blown. These motors pretty much do not blow headgaskets unless they overheat. Slow leaking head gaskets are also not an issue, these motors have aluminum head and block, theres no corrosion.

You water pump is most likely leaking, therefore your temp fluctuates and coolant is disappearing. Give it a couple more weeks and it will start overheating.

The white smoke from the exhaust is probably just moisture, which is normal, or maybe your power steering air valves is leaking.

Get your water pump replaced, and don't worry about the head gasket.

RA40

iTrader: (6)

Agree with the previous. If the car doesn't have chocolate milk looking oil, the loss of coolant is elsewhere, not a head gasket. Reservoir cap, water pump, radiator hose or thermostat housing leak...

Lsportline43

The thermostat was changed when the radiator was changed. Which was a month ago or about 5,000 miles ago.

The only thing is, the water pump was replaced at 183,000 miles. Would it start leaking prematurely? It's only got a little less than 60,000 miles or so on it. Car now has 238,500+ miles.

I will definitely check out what's going on with it and get back to you guys. I'm glad to hear that this motor is not prone to headgasket issues. I didn't think it was, that's among the reasons why I bought it.