geode

Greetings. I recently noticed the coolant reservoir was running low and smelled coolant after engine was running for a bit. No signs of leaking anywhere. Radiator new, head gasket replaced few years back etc..
I pulled the radiator cap and ran the engine to do a quick block test and after one hour running I am seeing no flow through the radiator. The temp gauge goes up to but never over 185. Could my water pump impeller have failed ? No strange noises coming from the pump or anything. I put a digital thermo in the coolant and it read 450 yet no flow. Any insight would be appreciated.

Thank You

mountainmanjoe

at 450F, coolant would no longer be liquid. If you have low cooland, and can smell coolant then you likely have a leak somewhere. Try a UV leak detection kit or pressure tester.

geode

My mistake. That should be 150. Tested it again and digital thermo reads 150 on coolant and 185 at gauge. No flow. Engine running for appx 45 minutes.

mountainmanjoe

if the pump failed I would expect the engine to overheat, so for now it seems the only problem you have is that it's losing coolant.

geode

I agree. But why no flow through the radiator. That has me stumped. I will do a pressure test as you suggested and look for a sign. Thank You Mountainmanjoe.

mountainmanjoe

it's possible for trapped air to cause issues too, so make sure it's all purged out. park on an incline so the rad neck is the highest point, run it and fill it all the way up.

geode

I will do that. Hills a plenty around here. I just ordered some UV fluid and will do the fill at the same time. I am trying to remember if I ever replaced the water pump in this thing. I know I did the radiator twice and the thermo at the same time. Only 140 K on this 2001 engine.