papasmithn

Symptoms:
1997 Lexus LS 400 - 184K miles


Slow coolant loss. Strange thing is, coolant looks at proper level until you remove cap and then begins to settle back into the engine/radiator.

Air or steam bubbles through reservoir

Temperature gauge has went into higher zone but, last time it didn't and had a lot of bubbles coming through the reservoir.

Have replaced thermostat but, still get some bubbles through reservoir

I am guessing either the head gasket or water pump. Really hope it isn't the latter as a google search indicates that is over a 2000.00 repair. Though the car is in great shape otherwise, that is a lot of money to put on a 18year old car.

But, do not detect steam from tailpipe or milky oil. Do have a oil level drop, 1/2 quart every 1000 miles.

Thanks in advance for any help or suggestions
Dave in SC

timmy0tool

iTrader: (7)

when was the last time you replaced the water pump? at 184k you are due for another timing belt change (90k interval) in which most folks replace the WP at that time since it's already accessible.

as for your coolant bubbling issue, that means the car is indeed overheating. the most common issue is air in the system, which will need to be bled out.

use this as a reference:
https://www.clublexus.com/forums/ls-...der-valve.html

https://www.clublexus.com/forums/ls-...ng-system.html

RA051823

Sounds like you might have a head gasket problem. You can have a oil analysis done to see if coolant is in fact mixing. Have you block tested the engine?

timmy0tool

iTrader: (7)

i wouldn't go that far into thinking it's the head gasket just yet. it's not common to hear about that problem in our cars, unless you overheated the car for an excess amount of time. these motors are resilient, when properly cared for!

bleed that coolant, it's a very easy to do!

dicer

If its a head gasket it will build up excess pressure and force coolant out.

papasmithn

Great information guys. It appears this forum is alive and well.

I think the bleeding procedure on my 97 LS 400 includes taking off the plug on top of the thermostat housing and putting some coolant there.

As it appears that the prevailing sentiment is that it is either a head gasket or water pump, as I suspected, I am going to have the cooling system checked tomorrow at a shop. I will let the forum know what I find.

Bill Dowd

LOOK DOWN BETWEEN THE RADIATOR AND THE AIR COND CONDENSOR FOR JUNK ALSO CHECK THE RADIATOR FOR BEING CLOOGGED AND IF IT IS CLOGGED DON'T WASTE TIME TRYING TO FLUSHING IT OUT JUST GET A NEW RADIATOR. I bought a radiator made in China and no problems in the 120-123 degrees of Palm Springs and 100's in bumper to bumper LA traffic. I use Toyota red antifreeze and distilled water 50/50 mix I hang out at a radiator / trans shop and see clogged radiators all the time good luck. ONE LAST THING THE FAN CLUTCH IF YOU CAN SPIN IT MORE THAN ONE COMPLETE TURN DUMP IT.

UNCJD

There's a lot of good advice here. Before losing too much sleep over the head gasket, burp the cooling system. But before you do that...,change the timing belt. If that goes, you're screwed and a $2000 repair will sound like a bargain.
If you're worried about dumping a bunch of time and money (or money, if you don't do it yourself) into a TB change on a car that may have a blown head gasket, you can pressure test the system using a tool from Autozone or whatever parts store you use. Go ahead and burp the system (http://www.instructables.com/id/How-...ooling-system/)
and then go ahead with the pressure test (http://www.ericthecarguy.com/engine-...ooling-systems)
If it holds pressure, then the head gasket problem isn't as likely and you can go ahead with the TB/WP change with confidence.
I'll confess that I'm a crappy mechanic. This advice is stuff I've stumbled across researching other problems, so I would seriously defer to more knowledgeable people on these forums. But if you watch that Eric The Car Guy video, that might point you in the right direction.

timmy0tool

iTrader: (7)

again don't jump the gun and think it's the head gasket already. simply bleed the coolant and go from there!

when i bled my coolant i parked on an incline with the front of the car at the highest so all air gets pushed out to the t-stat housing inlet. not sure if this is correct but that's my thinking.

PureDrifter

iTrader: (10)

want an easy way to bleed the coolant?

Buy a spill-free-funnel (aka Bleed Funnel)

1. Start with a cold motor, open the reservoir cap and set up the funnel with the correct adapters.
2. Fill funnel ~3/4 way with coolant/Distilled water mix.
3. Start engine, immediately turn heater to full HOT and fan to max. (Windows down so you don't bake)
4. Run engine for 10-15mins until it reaches normal operating temp (~1/2 way up the gauge)
5. Race engine from 2-3,000 RPM several times during the process. Be sure to keep the fluid topped off during this process since you don't want to run the funnel dry, that introduces air into the system.
6. Once all bubbling stops and the engine has been at operating temp for a few minutes, your cooling system is likely free of air. Shut off the engine.
7. Grip the upper radiator hose with one hand and squeeze so the water level in the funnel increases slightly. While it's raised, put the plug into the funnel and remove it from the coolant reservor. (Squeezing the upper hose then removing the funnel allows you to remove the funnel and have the cooland reservoir at the correct level once you release, so you don't spill any fluid when installing the radiator cap!)
8. Install the OEM radiator cap immediately, and enjoy

By doing it this way you don't worry about the bleed cap on the throttle body as the bleed funnel has become the highest point in the cooling system, so all air will travel to it.

UNCJD

What were your results?

papasmithn

I took it in just today after putting in a new thermostat and performing the procedures for "burping" the system. Since it doesn't look like oil in the coolant or coolant in the oil, and that along with losing coolant, I decided to have a pressure test done on the system. I will get back with results for others who might be having these somewhat confusing symptoms, at least to me.

papasmithn

Turns out that I had several problems with the cooling system. They included the Clutch Fan, Radiator and Water Pump. Since it was getting time to change out the timing chain, I did that as well. I also asked them to look into a loss of power steering fluid. Turned out being a bad high pressure hose. Total cost, $1323.00. Ouch! The car is getting old and this was a lot of money to spend on it but, now she runs sweet and, if I take care of her, should hopefully run a couple more years. Thanks to the forum for all the advice and suggestions.

Dave in SC

RA051823

These cars will run a very long time IF maintained properly. Looks like you're set for another decade!