2004 GX470 2UZFE 120,000 miles, purchased about 3 months ago. Timing belt and water pump replaced 4 years ago. Original rad and hoses as far as I can tell.
The coolant level in the overflow tank is dropping gradually. I noticed it was low after I bought the truck, I topped it up a few times and then it seemed to stabilize. After a highway run the other day the level was down again and needed to be topped up.
I've looked everywhere for a sign of a leak and can't find any (around water pump, hoses, sides of heads, rad, etc.).
Maybe there's a pin hole leak somewhere that is allowing coolant to vent while vehicle is at speed, and leaves no traces?
I replaced the radiator cap and no effect.
No sign of head gasket failure (spark plugs are clean, blue fluid tester for fumes at rad reveals no exhaust gases present, no noticeable fumes in the exhaust). I know these 2UZFE engines are not known for head gasket issues.
A bit of loss is probably natural, but I've probably added half a gallon of coolant since buying the truck, to top up the level in the overflow tank.
Any ideas on where else to look for where the coolant is going?
Should I replace the upper and lower rad hoses in case there's a pinhole leak I can't see?
Forgot to say: my mechanic did a cooling system pressure test today and all was good. He's also the one who looked at the spark plug condition and checked all around the engine for signs of leaks.
The coolant level in the overflow tank is dropping gradually. I noticed it was low after I bought the truck, I topped it up a few times and then it seemed to stabilize. After a highway run the other day the level was down again and needed to be topped up.
I've looked everywhere for a sign of a leak and can't find any (around water pump, hoses, sides of heads, rad, etc.).
Maybe there's a pin hole leak somewhere that is allowing coolant to vent while vehicle is at speed, and leaves no traces?
I replaced the radiator cap and no effect.
No sign of head gasket failure (spark plugs are clean, blue fluid tester for fumes at rad reveals no exhaust gases present, no noticeable fumes in the exhaust). I know these 2UZFE engines are not known for head gasket issues.
A bit of loss is probably natural, but I've probably added half a gallon of coolant since buying the truck, to top up the level in the overflow tank.
Any ideas on where else to look for where the coolant is going?
Should I replace the upper and lower rad hoses in case there's a pinhole leak I can't see?
Forgot to say: my mechanic did a cooling system pressure test today and all was good. He's also the one who looked at the spark plug condition and checked all around the engine for signs of leaks.
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