KBaileyTN

Good Morning - I have several issues that have either plagued or recently popped up with my LS400. I haven't had the car too long and have been fixing odds and ends as they become prevalent. The below issues have come about in the recent weeks and I need to fix ASAP



-Overheating - no apparent leaks in the system, water level stays mid to normal. Car will run normal for appx 2-5 miles then quickly raise in temp. When braking (not always) will hear some gurgling/popping sounds and then the temp will lower to normal but will eventually rise back up to H or close to.

-No heat unless engine is at 2.5 or higher RPM. The car will not blow heat at idle or low RPM. This issue has been going on for a while, mild winter didn't make it seem super important.

-Gurgling when putting water/coolant into the reservoir. Two days ago I was out and the car got to H. I sat and let the engine cool some and then added some water to the reservoir only for it to gurgle.

-Steam. When I stop and turn off the car there is steam coming from the front passenger side. When I raise the hood it seems to be boiling from the cap as well as from somewhere closer to the front end of the car...cannot tell exactly where it is coming from. The steam has that sweet coolant smell to it.

-When the temp gauge starts getting hot I turn the defrost on high and heat all the way up but with the issue above it doesn't seem to work.

I'm not extremely car savvy but can learn. I'm needing to know what I am possibly dealing with.

AandSC

I'll take a stab at this.

When was your timing belt last replaced?

It sounds as if your water pump may be leaking. It's attached to the front of your engine at the bottom. Your thermostat doesn't appear to be working either, which is at the front top of the engine, and would be why your coolant temperature heats up quickly.

If it were my car I would replace the water pump, thermostat, timing belt and associated pulleys and then flush the cooling system and refill with the appropriate coolant. Not a job to be performed unless you have a really good set of tools and some good mechanical knowledge. Parts to do all of this are reasonably inexpensive but labor is not.

Are your fans at the front of the car working?

KBaileyTN

I haven't a clue when any maintenance was done. My uncle who is a used car dealer bought it at a car auction. Sometimes a great price comes with other costs, like not knowing maintenance history.

I know some who are general mechanically savvy...they can do the work for me. They have somewhat busy schedules so I didn't want to bother them with trying to diagnose the issue when I can post here with other Lexus owners and get a better read of the issue.

As as far as the fans are concerned...now that it is brought up...when the car is hot and I stop I have not heard the fans run.

AandSC

If the fans aren't running then you may have a faulty coolant temp sensor. That's a cheap, easy replacement.

If you look under the hood you may have a sticker that states when the timing belt was last replaced. If not, you need to perform those maintenance items. Banshee365 posted a great DIY that explains what is associated with replacing water pump, thermostat, timing belt and ancillary equipment.

Banshee365

It sounds like your water pump isn't pumping properly. Regardless of the reason, your water pump needs to be replaced. Some of these symptoms also sound like a bad head gasket. That is pretty rare on these engines. Although it sounds like this engine had been overheated multiple times is a head gasket or two isn't out of the question. There aren't many things worse than overheating an engine, except running it without oil.

do not drive it until the water pump is replaced. If you want you can remove the coolant bottle cap while it's cold, start the engine, let it warm up a little bit, rev it a little and stick you nose in the bottle. See if you can smell any exhaust smell. Large air pockets can cause some of the symptoms you are having and large air pockets are created by leaking head gaskets when you have repetitive problems like this. I bet it all stemmed from a bad water pump though and I would be hopeful that that is your only problem. Replace the thermostat with an OE thermostat as well.

Amskeptic

Have you bled the system? There is a bleeder nipple right above the thermostat housing. My factory manuals are 1,000 miles away, so I cannot advise further.
Colin

Losiracer2

Fill coolant through the fill valve in the center of the engine, not at the reservoir. I have a feeling you're probably half a gallon low on coolant. My LS would make gurgling sounds just behind the dash and I would have no heat at idle, until I added some coolant.

KBaileyTN

No I haven't bled the system.

Ill probably be ordering a water water pump today. Is signs that the water pump is out have to do with spray residue under the hood and around the reservoir cap? I noticed last night there is this milky residue around the reservoir.

djamps

You are basically 90% of the way to replacing the timing belt by the time the pump is out. Might as well order a timing belt kit while you're at it. Dont forget a new t-stat and radiator cap. Something as simple as a bad cap can cause all kinds of these issues.

Losiracer2

and if you do a T-belt, might as well do the crankshaft and camshaft seals since those will leak right about this age. I had to do a T belt 30k early due to a petrified crank seal

deanshark

The residue around the reservoir is probably from either the coolant level sensor, or the cap leaking.
If I was you I'd try changing just the thermostat and radiator cap first to see if that works. And deffinately bleed the system afterwards.That's alot cheaper and easier then a water pump (and timing belt) job. Your T-stat could be stuck closed which doesn't let the coolant flow through. If so, then the water pump cant circulate the coolant which could cause the gurgling sounds and overheating.

Banshee365

Any coolant residue associated with symptoms like that is almost always purge from an overheating condition.

Jfonseca01

I was taking a short ride to the store and my car started overheating. I know I let the engine cool and checked out the coolant it was no coolant in it. Then I start the car and filled it up with antifreeze. After that I drove on the freeway about 3 miles and started getting hot again what could be my problem?

Jfonseca01

When I put the antifreeze in I didn’t hear any gurgling or popping noise. There was no there was no steam pouring out anywhere and there’s no leakage fluid under the car. There was absolutely no fluid in it so when I put the antifreeze in it took a whole gallon of antifreeze.

RA40

iTrader: (6)

It is going to need a good coolant burp to get any air out. Let it idle with the bleeder cap removed. During this burping check the ground for any signs of coolant leakage. Coolant doesn't disappear on a maintained closed system. Check the top and lower radiator tanks for signs of leakage. As well get under the car to inspect the bleeder drain **** on the lower radiator tank. The O-ring on these ages and drys out causing small but gradual coolant loss over time. The original radiators themselves usually have a lifespan from 160-220K with most being replaced about 180K miles, the hoses would be replaced as well.

Next is the heater valve check for any leakage by the firewall.