Yoder

Been trying to figure out this overheating problem for a week now. Last week my car just started overheating all of a sudden. Found that:

- Fan motors not turning on...fixed that w/manual fan switch I wired in
- Thermostat may not have been opening...put in HT 160 'stat

Car still wanting to run hot when idling and would boil out of reservoir cap if I didn't get it down by revving, etc. Next was a waterpump R&R.

Now today I barely made it home when it started leaking coolant like a sieve.

It's leaking out of the back of the pass. side head at a big bolt where the hard line coming from the throttle body coolant inlet meets.

I can pump it with pressure and air just blows right out...anybody know what this is?

I hope I don't need new head gaskets...let me know what you think.

Z95m6

Its the coolant cross over tube. You can buy the washers from GM, they are about $5 a pop i think.

Yoder

Thanks man! You rock!

I wonder if this is what led to my over heating or was due to it? Still need to figure out why it's heating up if this didn't cause it. Anybody know how to know if the WP is working or not?

I think the WP bearing squeaky for the last couple of months...maybe it gave out.

shoebox

You can see the coolant lines in this pic. A seal goes between the line and the head and between the bolt and the line. So you need 2 per side (total of 4).

Ryan's LT1

Make sure to THUROUGHLY bleed the system when you are done installing the seal and coolant cross over tube. You'll save yourself many headache's later on.

SS RRR

Worst case scenario you may have a blown head gasket causing excessive pressure which may be breeching a weak link (banjo bolt seals).
I would have a leakdown performed ASAP before driving the car anymore just to make sure what is going on.

Yoder

Man I was hoping I was out of the woods on the head gasket deal...thanks for the info. Not driving it till the problem is solved...took plate off WP and impeller looks corroded...like the wings are rusted off...I'll change it tomorrow.

Do crossover tubes go bad or get blocked up? Maybe I should get new ones while I'm there...

Guest47904

Any amount of air introduced in the reverse cooling system of the GenII engine can be bad. Although the coolant cross over tube is more likely your cause of the leak, it's not the direct cause of your over heating problem. By that I mean, it can't by itself cause over heating. If it's leaking air, the air pockets it may have caused, can be the source of the overheating.

The first thing to do is locate and eliminate all sources of leaks. Fill and bleed the system PROPERLY and go from there. At that point, if you still have the problem, then do a coolant system pressure test. A leak down test, which pressurizes the cylinders, will tell you if you have a leaking head gasket from the water jacket to the cylinder.

Another possibility is the intake gasket but other problems will show if that is the case. Don't discount something blocking the radiator either. Mine had a plastic grocery bag in between the condensor and the radiator. I found that by removing the top plate.

Dave89IROC

hmmm.......how is that possible when no coolant goes through them?......

Yoder

Shoebox or anybody...Do you know hot this seal is presed into the pipe? I was able to pull the outer seal out by reaching back there with needle nose pliers but I'm not sure how i'm going to get it back in....not to mention the inner seal.

Should I just pull the whole pipe out and work on it?

Thanks for the help...

Dave89IROC

huh?

they are just washers that go on the bolt...

BLACK LT1

[QUOTE=speedygonzales]Any amount of air introduced in the reverse cooling system .

Another possibility is the intake gasket but other problems will show if that is the case. ]


????

FWIW, as Dave89Iroc also noted, on the LT1, THERE IS NO ANTIFREEZE CROSSING THROUGH THE INTAKE. INTAKE IS COMPLETELY DRY - NO FLUIDS.

Yoder

Oh, OK. They were stuck on there so damn hard I thought they were pressed into the pipe like a seal. If they're just washers that's not a big deal. Thx

Dave89IROC

no problem, hope that fixes it

SS RRR

They are not just washers. They are a rubber seal encricled by a metal ring. The seal tends to stick to the cylinder heads from extreme heat.