Loss of Coolant

[AlexMW Lurker Find all posts View Profile Close AlexMW]

Recently when I start my V6 the idle was and is very rough. It smooths out after a while. I then started experiencing overheating on a long trip. (over 100km's) I notice I loose about 2 liters of coolant, the heat gauge goes up and then comes down. I have also noticed white vapour with droplets coming out of the exhaust. Has anyone experienced this problem? What was your diagnosis? I have done about 208000km's. Coolant reservoir stays full!

[Guest Close Guest]

Head gasket. Cracked head. Water leak. Have you done a compression test?

[turtlewa Member Find all posts View Profile Close turtlewa]

Next cold start take off radiator
Cap and lots of bubbles head gasket gone and engine off look under oil cap for white oil sludge and check dipstick
Sounds like gasket to me
Also when car is hot can steam out the rear pipe classic sign gasket

[LCP Lurker Find all posts View Profile Close LCP]

Hey Alex. Does not sound good mate. Had simular issues and ended up replacing my head gaskets. Big job, did not enjoy it. That was at 330,000 kms.
Before you jump to conclusions check your radiator cap is ok and holding pressure when temp is reached, it could be venting coolant out through the rad cap and then out of the reservoir. Does the reservoir fill right up?
Also might be worth checking the vent hole on the underside of your water pump, if the water pump is on its way out it could be losing coolant through there under pressure, might not be obvious so have a good look.

Just a few preliminary things to sus out.
Mick

[Brett1979 Avid PP Poster! Find all posts View Profile Close Brett1979]

As LCP mentioned the vent hole in the water pump can be losing coolant. It's a common culprit when the water pump internal seal is stuffed. Do you park your car on concrete at home/work? Check if any coolant has been left on the concrete. Pray this, the radiator or radiator cap is the reason and not your head gasket. Tearing the motor down far enough to replace the head gasket is a major job. If there's no "visible" sign of green coolant leaking then it's bypassing inside your motor which is not good. Check under the oil filler cap for a creamy whitish residue which means you've got coolant in your engine oil (head gasket leak). If you've been losing coolant for quite a while and it's gradually gotten worse then it's likely you've been topping up the radiator with water which will make it difficult to locate a visible leak if the coolant has been watered down enough to lose its colour. Tap water will corrode the spindle inside your water pump and God knows what else over time.

The likely reason for the coolant reservoir staying full is because you're losing coolant so quickly now. The cooling system is not pressurising properly. You're losing coolant at the rate of a drop per second to lose 2 litres over the coarse of 100km. Your temp is fluctuating up and down because when you drive it's just enough to keep coolant pumping through the top hose a bit. At idle your temp probably soarse because there's no coolant going through the top hose. The head is highly resilient in a Prado and can put up with overheating many times, but it's never ideal and there will be that time which will be the straw that broke the camel's back.
If the cause for the leaking is the water pump vent hole and not a head gasket failure, it will leak a drip at a time when the engine is cooler in temperature such as cooling down or warming up due to pressure backing off on the seal. When it leaks at running temp then it's completely stuffed and get your water pump replaced ASAP.

[Whitey Shockie Maker of the Month Award Find all posts View Profile Close Whitey]

Hey Alex,

What year is your 120?

It's common to see a head gasket leak on number 6 cyclinder on the 1GR-FE for early models, check this video;

https://www.youtube.com/watch?v=LM4Rfq-wvag

Good luck getting it sorted!

Best

Mark

[Whitey Shockie Maker of the Month Award Find all posts View Profile Close Whitey]

...another unfortunate South African here;

http://www.pradopoint.com/showthread...sket-on-1GR-FE

[AlexMW Lurker Find all posts View Profile Close AlexMW]

Hey Guys,

Brett1979, Whitey, LCP, Turtlewa & Piggy your response and suggestions and advice have been invaluable. What a great group. I have always been able to smell coolant when the car is hot but I will follow Brett1979's suggestions and check the water pump. Whitey thanks for the video link. I just wanted to say thanks before I do.

Much appreciated!

[AlexMW Lurker Find all posts View Profile Close AlexMW]

Hi Guys,
This is a strange one for you. I took off the radiator cap, started the vehicle and water pushed up with no bubbles. Reservoir tank remained full. I checked the water pump for leaks and found none. Checked the cylinder head and found no evidence of antifreeze residue. Checked the exhaust but there was very little vapour and no water. I drove for about 10km's and the heat gauge remained normal. Getting back to this white vapour - my BMW V8 also blew out white vapour and did not have a blown gasket. Can someone please explain this white vapour as I have seen it out of a lot of vehicles - why would it indicate a blown gasket? My Prado is black and looks like a hearse - must be a darn ghost in it!!

[stanmiko Member Find all posts View Profile Close stanmiko]

Could it be steam? Created by condensation in the exhaust system/muffler that is heated by the exhaust coming out? Caused, traditionally, by many short trips.

[Brett1979 Avid PP Poster! Find all posts View Profile Close Brett1979]

I dunno what causes the white vapour. I get it a lot with my car when starting it. Morning, afternoon, doesn't matter. Some white vapour comes out at idle until the car's warmed up unless the weather is quite warm. It's done this for the last 100,000km and it's not losing coolant as a result so who knows. That's why I didn't entertain that idea with what the possible cause could've been with yours.

So has your car lost coolant again since or is it all good now? Might've been a radiator hose not clamped on tight enough. If you've got the screw clamps do them up equivalent to as tight as you can with a flat head screw driver. I've had small leaks due to this so I always do the clamps up TIGHT now. But that's unlikely to be the cause of a major loss of coolant. When you checked the water pump and front of the block you obviously removed everything in front of it to expose it by the sounds of it? If the coolants still green, where it's been leaking will remain wet with it because it doesn't evaporate off very well or will be stained white after prolonged leaking. It'll be fairly easy to find. It's just got me puzzled if you can't trace it and there's no signs of the engine oil being contaminated with coolant.

Thermostat O ring??

[AlexMW Lurker Find all posts View Profile Close AlexMW]

Brett1979 = Greetings and thanks for your reply. Is it possible for a Thermostat O ring to not open for a short while? I am gonna take it for a pressure test up in our nearest town as I need to make sure I cover all possibilities. Fingers Crossed.
Alex

[AlexMW Lurker Find all posts View Profile Close AlexMW]

I wanted to ask, can I mix anti freeze. I have Toyota anti freeze in my system and I have purchased an anti freeze from a spares shop. Can I top up with this as I find the Toyota anti freeze very expensive in South Africa.

Regards,
Alex

[Guest Close Guest]

No you shouldn't mix coolant. It may gel up and block the radiator.

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

It get's cold in SA?