Ugh.. pretty sure I have a blown HG or cracked or warped head

[rikyric]

Temperatures have been 35-40 degrees lately. Would the clutch fan take longer to engage due to the ambient temperature? I'm just thinking out loud. Just because the temp gauge on the cluster reads hot or 3/4 doesn't mean the fan should engage.
Thoughts?

I haven't had time to work on the car, other than replacing the leaking temp level sensor, And that has seems to stop the leak. I let it sit and idle for about 5 mins and it barely went over the half way mark on the temp gauge. (hence my thoughts on the outside ambient temp not letting the fan engage) I am going to let it idle for longer tonight (30min)and see if it overheats.

[rikyric]

Well I found a crack in the radiator. Let it run for about 20 min, it started to go past the 3/4 mark. So I turned on the ac to turn on the aux fan and max heat the same time and that brought it back down to the center mark. So right now everything points to bad fan clutch and the leak in the radiator.

I found the leak/crack in the radiator after I had let it run for a while, shut it off and listened for any leaks. It was cracked at the overflow outlet that leads to the reserve tank. It was small but I could see hear the hiss from it.

[dude8383]

Nice work :up:

[ForcedFirebird]

Temperatures have been 35-40 degrees lately. Would the clutch fan take longer to engage due to the ambient temperature? I'm just thinking out loud. Just because the temp gauge on the cluster reads hot or 3/4 doesn't mean the fan should engage.
Thoughts?

For future reference, the fan clutch does engage more the higher temps.

To test a fan clutch, roll a newspaper section, get the car to operating temp and shove the newspaper in the blades. If the fan stops, the clutch is bad, if you shred the paper, it's good (a corrugated cardboard box flap folded in half also works).

[M10Power]

Chiming in re temp gauge

Read through this thread as I am wondering about the cooling system in my 84 318. Three months into ownership of this coupe, and the temp gauge has been indicating normal op temps. But about 2 wks ago, driving to work in sub-zero temps (Bellingham WA) and the temp gauge steadily (& v unexpectedly) crept towards the red zone. My commute is slow (40mph) on secondary roads for about 20 min so no real heavy load on the motor and again it was v cold out. But the gauge was pointing to the right, and then the motor would cool when I'd coast down a hill and the indicated temp would drop (so I felt confident the thermostat was responsive/normal.)

Instinctively I cranked up the vent to pull hot air out of the engine but it blew cold. Got me thinking the water pump wasn't working. Got to work, popped the hood but nothing seemed amiss - motor wasn't abnormally warm, no glowing headers, no chocolate shake. But 8 hrs later, on the drive home, temp gauge indicated normal the whole way. (It read "cold" at startup and warmed up normally.) Next day, same, no issue, so I thought the gauge was being finicky.

So last night, gauge acted up again. Ambient temp about 40 but the gauge indicated hot. Vents blew cold. Limped it home, stopping twice to be sure I wasn't blowing HG. And I should add - as I posted the other day - the exhaust has been blowing a LOT of water vapor in the am. A LOT. No, not coolant - it dissipates after ~5 min. No apparent coolant loss, and my fan seems to work fine. I don't think the heater core is shot - again, no coolant loss, no puddles, no coolant smell.

So I am wondering - what's the chance that my water pump has been dead for some time, and because my drive is so short and mellow, the car has been operating without a cooling system at all, and the thermostat's only reading hot *some* of the time, not all of the time?

After newspaper test in am, should I test water pump next? (I sense that lack of hot air through vents is a water pump or heater core problem, NOT a fan problem, right?) Pelican suggests my water pump impeller could be unreliable plastic and replacement would have metal impeller.

What am I overlooking?

[rikyric]

M10Power, it sounds like a water pump or clogged radiator. I picked up a handheld laser thermometer at harbor freight and it has helped me a lot, recommend picking one up.

I did work on the car today, replaced the radiator and fan clutch. And just my luck... the new fan clutch was bad... ugh. After I topped off the antifreeze and burped the system. Took it for a spin on the highway to let it get up to operating temp. Everything looked good no leaks... then I let it sit and idle for about 5 min. The needle started to creep past the half way mark! damn!
I got out and tried the newspaper test and could stop the fan with ease. I could even spin it the opposite direction. So I ordered a new one online, wasn't gonna pay $100 at the local parts stores.

Just for giggles I ran the car again, let it idle and as soon as it started creeping past the half way mark I turned on the heat full blast and it kept the needle steady at center.

So now I wait for the fan clutch to get here haha...

[rikyric]

Man... I cannot catch a break. What are the odds my water pump is now going out?!

I noticed a coolant leak on the driveway, checked all the hoses and they were good. Leak is coming right under the water pump and leaking down the front of the block. Also noticed a little coolant getting flung around by the fan.

So.... I ordered a new water pump, timing belt, tensioner, and all seals. I got the new fan clutch today but now gotta wait for the other parts.. gotta love it.

[ForcedFirebird]

Check the front freeze plug behind the cam gear too. I have had them get pin holes lately at the shop.