97 LX450 coolant loss (1 Viewer)

[sixsracing]

Been awhile since I've been here, started my own business a couple a years ago and got no time. My LX450 has been using coolant at an alarming rate (2 quarts every 300 miles or so) and I cannot get a handle on it. Here's what I know.
170,000 miles on vehicle.
No evidence of coolant in the crankcase after 1500 miles.
Small amount of unidentified substance in coolant recovery tank.
Initial startup pressure in cooling system rises to 14 PSI rapidly, then tapers off and maintains for 20-30 minutes, then falls to 7 PSI and maintains.
Spark plugs were removed and inspected for deposits, no problem found.
No overheating condition, not at idle, not around town, not on highway.
No visible leaks, although there seems to be a small amount of wetness at timing cover below water pump.
No contamination in transmission fluid.
Vehicle idles and runs excellent, no hard or pending OBD codes present.
Coolant was checked for acidity+nitirites no problem found.
No anti-freeze smell or excessive vapor from exhaust, even idling in garage for 40 minutes.

I am a capable tech and this being my wifes ride it's giving me fits. I really don't want to take the time to pull this motor down if I don't need to. Any help will be greatly appreciated.

 

[breathed]

That's a lot of coolant. It has to be going somewhere. Clean the engine and underside and check often. Do you have rear heat? Did you check those lines over the cats?

 

[Gordopescado]

I'd say pressure test the system at the radiator. Sounds like the water pump, once under pressure watch that spot below the w/p. I agree with brethed on checking the lines above the cats.

 

[Ting]

Send oil sample test to blackstone

 

[sixsracing]

Hey guys thanks for the quick response.

The rear heat works fine, lines are dry and the carpets are too.

I have pressure tested the system, almost 30 minutes at operating temperature. No leaks, however I did think that the spot at the timing cover I mentioned earlier looked more damp. Cleaned it up and couldn't verify leak. I took the splash cover off the bottom (by the belts) tonight and cleaned more thoroughly. There is some discoloration or residue on oil pan and it's coming from that general direction. But with the amount of coolant it's using I expect more than dampness. Water pump appears dry, I can get a finger under the pulley and the seal is not leaking at the shaft. Is there a bleed hole on the bottom of the pump? Can't see it from any angle I have tried and have never had one off.
As far as the oil test, we are talking over a gallon of coolant in 1500 miles, the crankcase would be overfull and discolored at the very least. Good thought though.

Again, thanks for the input.

 

[landtank]

stsrtup pressure when cold goes to 14 psi, not good. The only thing that should build pressure in the cooloing system is the expanding coolant from being heated. How's the HG fund?

 

[Gordopescado]

Pressure test with one of these, a radiator pressure tester. They allow you to put pressure in the system while you watch/ listen for leaks without the engine running. Great tool.

 

[sixsracing]

Good morning. Yes, I was concerned when I saw the rapidly rising pressure also, however, it stopped at 14 PSI which is not unacceptable. If it had kept rising then I would have assumed coolant system was open to combustion chamber. But it stopped and maintained, then dropped. Yes I do have a pressure tester, the exact model as in the photo actually. Are water pumps a common failure part at this mileage?

 

[Michael Hanson]

Top or bottom seams of radiator.Lower radiator hose,water pump leak in rear or underneath pump. Mike

 

[scottm]

IdahoDoug should be chiming in about the UV flourescent dye he used to verify his bad head gasket. It sounds like he had great luck with it, works well for finding coolant leaks. I think you can buy the kit at auto parts stores.

 

[98 SNAKE EATER]

stsrtup pressure when cold goes to 14 psi, not good. The only thing that should build pressure in the cooloing system is the expanding coolant from being heated. How's the HG fund?

ding ding ding!!


That's definitely a lot of coolant loss

If everything else checks out, put a catch can on the end of the over flow tube and drive it hard (don't just idle it)

If anything gets puked out, the radiator cap might be bad (a weak cap spring would let coolant overflow, then suck the remaining coolant back in when from the overflow bottle when it cools down)

That being said, I'm with Rick on this one

 

[mainemike]

If it is a HG, with that much coolant loss wouldn't you see and smell major tailpipe smoke? Or could it be consumed without a trace?

 

[sixsracing]

I have driven it as hard as 2 hours at 75MPH + on the highway and then turned around and did it again. There is no trail from the overflow hose, dry inside also. I just replaced the radiator cap last week with a factory cap, I felt the old cap was not holding pressure and I noticed a rip on the gasket. I have cleaned off the top and lower radiator seams and they remain dry.

I am interested in what Michael Hanson has to say about the leak under the water pump. Has anybody experienced a leak there? I visited the dealer this morning and could not get a good diagram of the housing arrangement.

All this input is very appreciated. Thanks guys.

 

[Squash]

Try the hose clamps...switch to gear clamps.
Seems that under constant driving you can have slight misting which over time leads to coolant loss.

Had the same problem once and it was the lower clamp.

 

[aclos3]

I had similar coolant use on my cruiser shortly after I bought and was convinced I was losing my headgasket. It turned out that the coolant flush I performed a week prior caused the clamp after the heater valve to leak. The leak was not really present at idle, but I finally noticed it after having a buddy hold the truck at higher rpms while I looked everywhere. The leak was very tough to see from the source and I only noticed when I had my head under the truck and looked up at all the hoses.

The leak originated from the horizontal proportion of the 90 degree heater hose. I added a second hose clamp and tightened them both and have yet to lose another drop of coolant. I suggest having someone sit in the truck and hold it at 4000 rpms while you observe the entire coolant system from every reasonable angle. It may also help to take the truck on a drive to get it thoroughly warmed. I can't comment on the pressure check, but you don't seem to have any of the other telltale signs of a head gasket failure. I would look to the hoses, pump, radiator.

 

[Beowulf]

... we are talking over a gallon of coolant in 1500 miles,

If this is an external leak then you are going to see dried pink traces of coolant all over everywhere (assuming you are using Toyota Red.)

It is getting past a HG and into your combustion chamber and out your exhaust and/or it was boiling off due to the bad radiator cap and you were losing it out the overflow and the cap. If the cap was the only problem then you wouldn't be still losing coolant.

-B-

 

[sixsracing]

Thanks for the tip on the hoses, I will be checking that next.

Beowulf, I'm trying to follow your thought here, if it is getting into a combustion chamber at the rate I'm losing it, I assume I would have deposits on the spark plug and at least a small cloud of coolant at the tail pipe. I have neither. Believe me, HG was my first thought too. Have people confirmed HG failure with no overheating, no deposits, no bubbles, no oil contamination and no exhaust plume?

I did check into the dye/infrared tool. Probably should have one anyway. $130.00 from my local supplier and may be picking one of those up this week.

Thanks again for the ideas, keep them coming.

 

[Beowulf]

Beowulf, I'm trying to follow your thought here....

Nothing complex on my thoughts. 1 gallon of coolant in the past 1,500 miles is a LOT of coolant loss. It won't evaporate into thin air unless you are boiling it off through the radiator cap or in the combustion chamber. You would see it if it were coming out of the water pump. This isn't some minor seeping going on. Are you using Toyota Red coolant? If yes, it leaves a very visible pink footprint where it is leaking. Don't know about other brands so that is why I am saying that you would see tracks if 1 gallon was missing through an external leak.

You said your rad cap was bad and you replaced it. If you are still losing coolant at that rate then the only logical place left for that much coolant to disappear is in the combustion chamber.

I did check into the dye/infrared tool. Probably should have one anyway. $130.00 from my local supplier and may be picking one of those up this week.

NAPA sells the dye for oil around $5/bottle. Coolant dye should be in the same price range. Get yourself a 110v black light (UV) at the hardware store. If that doesn't suit you then NAPA sells a little kit that contains a weak UV flashlight and some yellow glasses for about $16. The glasses help but the UV flashlight didn't cut it for me and my oil leak.

-B-

 

[sixsracing]

Thanks for the tip on NAPA, I have an account there and may go that route instead. I am using red coolant, have been since I bought it 70,000 miles ago.
I hear you on the limited choices of where the coolant is going. I just can't get my mind around the lack of other evidence. I will be taking a 300 mile journey today so we'll see what happens. I double clamped the lower hose below the water pump and put a worm drive clamp on the bypass hose to the intake because it was loose. Who knows? Maybe I will learn something new.

 

[sixsracing]

First 150 miles down I used very little coolant, maybe a pint or so. The return trip used about 2 qts. I did very little idling going down, stopped for a car wash and was stuck in line for 15-20 mins. waiting. I have noticed in the past weekds that the slower the vehicle is driven, the more it uses. Makes no sense to me, but seems to be the case. Got underneath as soon as I got home and see no residue or drips.