Coolant Leak by Plug 3

[joelittel]

The car is an '80 FI

I discovered a coolant leak by spark plug 3 this afternoon. I was letting the car warm up and planning to adjust the idle speed when I noticed steam or smoke coming off the top of the engine. Upon inspection I discovered this.



I was reluctant to stick my nose down any closer with the engine running, but to me it looked like the coolant was coming from either the bolt in the center of this photo or somewhere very close to it.

Could this be the result of a bad head gasket? I'm really hoping this looks worse than it is...

[RRoller123]

Check if it is running down from the throttle plate heater via that small hose off the side of the T, then dripping into the head area? The TPH is prone to corrosion and leakage.

(is that a custom insulation cover you put over the air intake hose?)

Pete

[joelittel]

I took my throttle plate heater off last year, and for just that reason.

The black rubber air intake hose was replaced with one of Mark's aluminum setups and I covered that with a heat shield by thermotec (http://www.thermotec.com/products/14500 ... hield.html) I believe auto zone sells the same one online.

The sleeve is a tight fit as far as width goes and a bit of a pain to lace up if you are at all particular about how it looks. Other than that I am happy with it.

[RRoller123]

So if the puddle is only in the pocket at plug 3, and nowhere else, and not dripping from a line, it must be leaking quite locally, probably from head bolt?

[joelittel]

That's what I thought. Is the bolt in the center of my earlier picture a head bolt, and if it is leaking from a head bolt (or that bolt) what are my options?

[RRoller123]

someone with a lot more knowledge than I will have to answer that.

[joelittel]

Right now I'm hoping it's as simple as a gasket gone bad... The good news might be that a new set of cams for a fuel injected street car "could" find their way in there, as long as I'm going to be taking the head off to check the gasket.

[fiatmike124]

I would really be suprised if a head bolt was leaking like that. I would soak it up and try to dry it off as much as possible and then see if you can determine where it is coming from. Check the temp sensor that is right next to cylinder # 3 (it is hidden in your photo but would be just to the right of # 3). Good luck

[joelittel]

I will definitely look at that sensor.

Any idea what I should torque it too?

[TX82FIAT]

If you mean the head bolt then 59 to 62 pounds depending on what manual you read. After you cleaned it up did you put a torque wrench to the head bolt in question. It seesm like a lot of coolant to come up from a head bolt like that unless it is very lose.

[RRoller123]

my bet would be on the sensor.

[joelittel]

I only cleaned it up, and have not yet checked the bolt to see if it was tight.

Would you happen to know what the sensor should be torqued to?

[RRoller123]

I don't, maybe someone else will chime in.

[bradartigue]

Looks like coolant is on that 90 degree hose you have coming up between 3 and 4.

If you have that much coolant coming up through a head bolt then your head gasket is nasty enough to be burning coolant, so clean the plug hole and pull the plug. If you're burning coolant it will show on the plug. I've really never heard of one coming up through a bolt like that, and that coolant is real clean, unlike the coolant/oil nasty mix you'd likely have from a head bolt.

I'm thinking the sensor is leaking or the tap hose between 3&4, and if you clean it up and then watch it while running you should see it start leaking. Get it all cleaned up and watch the show.

Sensor torques - they don't have to be super tight but I've had to apply 50-60 ft lbs to remove them before. I've never gone more than 30 ft/lbs with those because they're brass and seat well. I have put tape on the threads before (teflon tape), just to make myself feel better, but you shouldn't need it.

[joelittel]

So far I can not get the leak to happen again. I let it idle in the driveway for two fan cycles, took it for a trip to the auto store, and let it cycle the fan again in the driveway.

Once it cools down I'll check the plugs as suggested.