Howdy,
I've started my LIM gasket job today and wasted lot of time to drain the coolant from system via petcock valve.... I can see it turning, but nothing flows out from the radiator. Finally I gave up and simply pulled the hose.
I guess it's damaged. Now I am trying to find that petcock assembly, to make sure it is not going to surprise me with an unexpected coolant leak one day. No luck. Just wanted to ask - is it something I should be worry about? Anybody knows? Do they come as a spare part or they come together with radiator?
Cheers,
Mike

 

They usually don't come out of the radiator, it just backs out enough to let the coolant flow out of the opening. It sounds like that if you get it out it is going to start leaking. I had the same problem, had to replace the radiator. Luckily I had a life time warranty.

 

I unscrewed mine all the way from the radiator. Its just an oring that seals it.

Now as to the cause of what you're seeing, I'd bet its rust and junk caused from the Dexcool. The drain petcock should be the lowest point in the radiator, so its probably where all the crap collected and caused a blockage. When you do your LIM, take a good look at the water passages on the manifold, especially near the rear. I'm betting you're going to see a lot of missing aluminum. I replaced my spider with an updated model and in the process got two LIM sent to me. One was from a newer vehicle and wasn't too bad for corrosion, but the other one had tons of missing metal. I don't think a gasket could have sealed it.

 

Thanks for the advice I think I'll try to flush the radiator and see if it solves petcock problem.
As for the manifolds - I've drained mine into an ultrasonic cleaner. It came out as if it was casted yesterday


I do have some spots of missing aluminum, but nothing big. I'll burnish the surface till I get a mirror:

I find doing the LIM job (I to some other things too) very profitable - it gives me a new level of confidence about my car. I am crossing my fingers not to get back here with a well-known topic "engine does not start after LIM".
Cheers, Mike

 

I may have a good moment to flush the radiator and a cooling system now. I assume, I should start with a radiator first, then, once the petcock starts working on, flush everything via petcock.
I wanted to ask what would be the best method? I am not sure whether shall I disconnect hoses from radiator and try flushing with a water? Or maybe in series with a coolant pump? I have to beat the crap out of it
Cheers,
Mike

 

Didn't even try the petcock. I can't get my hands in there and I've read too many horror stories.

I just pulled the lower radiator hose. Have a large jug handy and make sure no pets are around.

 

I went a similar way to drain (partially) the coolant for doing LIM gaskets. The lower hose tends to be a most convenient way of draining the system.
Except, the method is for draining, not flushing.
Facts is, I do have some sludge into my radiator, that blocked the petcock. How big is the amount? I don't really know. But a lower radiator hose mount is located approx. on 1/3 of the radiator total height, so the sludge amount may be clogging up to a 3rd part of my radiator. That also has an impact on cooling efficiency.
If I were living in US I'd probably order a new radiator, but since when transportation time is a factor here, I am looking of a method how to flush that crap out. Not necessarily through a petcock.
I hope that address my problem more accurately,
Cheers,
Mike

 

If you don't have one of these, get one. You'll wonder how you ever got by without it.

 

Thanks Tom,
Never seen these before. Just watched a YT video and looks a nifty gadget to have in a garage. I liked it
Things they don't say it is not for a coolant. The cooling systems do not have dipsticks, but the tanks with a level marks and an overflow lines. Moreover, it is all located above, on top of the other cooling system components...
Cheers

 

Those radiator petcocks are a PITA, they remind me of cheap home water heaters with a plastic drain valve. Cant get an angle to looseen them, They are seized or don't drain. Lower hose drain, fill, run drain, rinse and repeat. Mine also is intended to be removed and is sealed with an o ring.

George