Using coolant!?

[Mix90 Lurker Find all posts View Profile Close Mix90]

Had car serviced because i had noticed it had used a bit of coolant and temps ran slightly hotter when under load 4wding. Had the cooling system pressure tested which it past. Now 3000km later while 4wding again I had to top it up with 3l of water to get me out of trouble. Checked oil cap no residue or signs of water in there. No obvious leaks anywhere and no bubbling of the radiator when cap is tacken off. Any other signs to check hoping I haven't blown a head gasket. Engine has 180000 on the clock and runs fine. Any ideas what's going on?

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

Is your Prado an Auto? There's only so many places the water can go.

1. Coolant could be leaking into the oil system - you said there was no sign of this

2. Coolant could be leaking into the combustion chamber/exhaust - Test 1:Check the reservoir bottle for the smell of exhaust. Test 2: hold a piece of card board near the exhaust pipe for a few minutes while the engine is running at operating temp and check moisture build up in the card board and the smell of coolant

3. Coolant could be escaping into the atmosphere - Is there any obvious leaking in the engine bay?

4. Coolant could be mixing with the automatic transmission fluid - check the ATF dip stick and make sure its a nice clear, red/pink colour.

[letsgoplaces Advanced Member Find all posts View Profile Close letsgoplaces]

Mate i had exactly the same issue. After cleaning out the radiator, replacing the radiator cap to ensure correct pressure was at the cap, replacing the thermostat, repacking the viscous clutch oil then finally replaced the radiator. After each 'fix it', the problem got better each time, and now after all those jobs were done there hasn't been an issue since. I never had signs of leaking and hot and cold pressure testing held pressure. So don't understand why the tests didn't show an issue but....

Anyway, hope this helps a bit

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

Could be your water pump, It may only leak when the engine is running and you have a pressure buld up.

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

had a similar problem with a corolla where the head gasket was leaking into the cylinder and burning off the coolant but not showing any other signs of a head gasket problem .

[Mix90 Lurker Find all posts View Profile Close Mix90]

Prado is a manual but looks as if it has an auto radiator as has other outlets which i'd say autos use. This may be standard but just what someone told me. Very usefull advise think i will take it to the mechanic get it checked over but thinking of replacing thermostat and checking waterpump etc.

[Evo's 90 Lurker Find all posts View Profile Close Evo's 90]

I had a similar prob with loosing a little coolant but no overheating, found y water pump to be leaking a little but it would dry up before anything ran out from behind the timing cover, I only found it because I was curious if the timing belt had been changed and had done 220,000km and didnt trust the guy I bought it from, the belt was no far of snapping also found later the same prob with my radiator, had a small leak in the core but was drying up before hitting the ground.

New water pump, timing belt, all pulleys, seals and a new all alloy radiator off evil bay which is twice as thick, twice the cooling capacity, problem fixed. Some mods needed for bigger radiator though...well worth it

[Evo's 90 Lurker Find all posts View Profile Close Evo's 90]

Evo, was that the ASI brand of radiator or what?
The Roo.

yes mate sure is, the radiatorin general lookslike good quality the only thing i wasn't happy with was they used nutsert's in the aluminium frame and looked like they might pull out, I knocked them out and used stainless nuts and bolts.

the only other thing is because of the square edged aluminium tanks the stanard bash didnt fit back on, some mods needed there, but mhy brown davis fits no prob.

they only seem to make them for with the auto cooler, so I would think anyone with auto would need and external cooler if going down this path.

[Mix90 Lurker Find all posts View Profile Close Mix90]

Ended up being the radiator. But was only evident when pressurized with air in a tank. Replaced with genuine Toyota radiator glad it wasn't a head gasket.