Head gasket is failing, plus weird post-Weber issue

[mr_ed]

Greetings,

 

First time posting, but been lurking for a time. Awesome website...it's been a real help with my 1983 wagon. I picked it up in Washington back in May in preparation for transferring to Kodiak Alaska. Figured it'd be a great island beater-with-a-heater, and it has. Considering the island's max speed limit is a few miles of 55 mph, the 4 speed is right at home.

 

So, first thing, I believe my head gasket is failing. After I got it, I noticed that the radiator was only about half-full of coolant. I'd heard that these cars tend to have an arbitrary preferred coolant level, and after I did the weber swap, I topped it up and sure enough it went back down to about half-full. However, after getting to Kodiak, I noticed that it was lower than half, so I topped it back up. Then I noticed my oil level was steadily rising on the dipstick.

 

I used genuine intake manifold gaskets after the weber swap (as per everyone's suggestions here), and there's no coolant smell in the exhaust. I pulled the valve covers to check those freeze plugs that I've heard can spring a leak, but they showed no evidence of leaking (both valve covers were a milky mess on the inside, and I triple-checked my PCV routing. It's correct). So I'm pretty much resigned to the fact that I've gotta pull the heads. Does anybody have any other ideas of what I should check before I proceed. This is my first EA81, so I'm learning their ways.

 

My plan is to get the full Fel-Pro gasket set off Rockauto, plus OEM intake and exhaust manifold gaskets from a dealer. 

 

My second issue (which may be related to the head gasket? Cooling systems can be finnicky) is that it starts overheating when I turn the heater on. This issue started immediately after putting the weber on (I used an EA82 manifold and weber kit as per the how-to's on this forum). While driving around with the temperature selector lever on COLD, the temp gauge stays right at the operating mark. The minute I move the lever to HOT, the temp gauge will start climbing within 30 seconds. It keeps right on climbing until I move the lever back to COLD, at which time the temp on the gauge will promptly return right back down to the normal mark. I've done this multiple times (always making sure I didn't let it overheat), and it does this religiously.

 

This has me befuddled. I used a genuine OEM thermostat when I did the weber swap, and I tested it and it passed. I'm not leaking coolant from the heater core or valve. And if the core was clogged, I don't see why it would cause the temp to rise...it would just be as if I didn't open the heater valve....right?

 

While googling this problem, the closest thing to an explanation I could find was that when you select heat on the dash, it opens that valve and allows all that cold coolant that's been hanging out in the heater core to rush to the thermostat, which cools it and closes it despite the engine being at operating temp and needing it to be open. However, if I try having the heat on from a cold-start, once the engine begins to warm up it will keep right on warming up towards overheating until I move the lever back to cold. Also, I never saw the above scenario mentioned with Subarus...it was always SUV's (4Runners in particular) that had rear heat, so they had a ton of cold coolant running all the way back to the rear heater core, and back to the engine. There shouldn't be enough "cold" coolant in the Subie's heater core to create this problem.

 

Just curious if anybody's experienced this sort of thing before. I know my head gasket is definitely a smoking gun, and they can cause all sorts of funky cooling system issues, so I won't be jumping to any conclusions over this until after that head gasket is remedied.

 

Cheers!

 

Ed 

[BratWarrior]

Something you should check is the coolant passage under the carb that contacts the adapter. This passage MUST be blocked and blocked well. A tiny piece of screen material and jb weld will do the trick. Also, the jb weld must be sanded down so it is PERFECTLY flush. That's my 2 cents

[Flowmastered87GL]

I think the issue was addressed above by BratWarrior.  What I did on my EA82 manifold was grind down the little pipe that comes into the base of where the carb adapter goes (to make it flush.  Then I filled that hole as much as I could with JB weld and sanded it smooth.  The way I dealt with the coolant hose that wanted to come into the base of the manifold was to insert a stud into the hose and clamp it down with a hose clamp (so its a plug)

[mr_ed]

I'll check that passage to make sure it's holding when I take the manifold off for the head gasket, but I don't believe it's leaking. I filled it with Aluma-Weld prior to installation, and I put the manifold on a mill and machined the carb adapter mating face and the manifold-to-head mating faces perfectly smooth.

 

Just to be sure I'm tracking, the passage you're talking about is the one that would send coolant into the factory Hitachi carb, correct?

[BratWarrior]

I think the issue was addressed above by BratWarrior.  What I did on my EA82 manifold was grind down the little pipe that comes into the base of where the carb adapter goes (to make it flush.  Then I filled that hole as much as I could with JB weld and sanded it smooth.  The way I dealt with the coolant hose that wanted to come into the base of the manifold was to insert a stud into the hose and clamp it down with a hose clamp (so its a plug)

 

Yup.

 

 

I'll check that passage to make sure it's holding when I take the manifold off for the head gasket, but I don't believe it's leaking. I filled it with Aluma-Weld prior to installation, and I put the manifold on a mill and machined the carb adapter mating face and the manifold-to-head mating faces perfectly smooth.

 

Just to be sure I'm tracking, the passage you're talking about is the one that would send coolant into the factory Hitachi carb, correct?

 

That would be the one.

[mr_ed]

Yup.

 

 

 

That would be the one.

So I was thinking on this one and I'm confused. If that passage in the intake manifold under the carb was leaking, how could it cause the car to ONLY overheat when the heater valve inside the firewall is opened?

 

Unless that passage in the manifold is connected internally to the return side of the heater line (therefore letting coolant that's returning from the heater core to escape into the intake, thus compromising the cooling system), shouldn't it either have no affect or cause the car to overheat regardless of the heater valve position?

[rdweninger]

You are low on coolant.   When you open the heater, your already low level is redirected to heater core, thus less coolant moving thru radiator thus temp rising.