Oh noes! (cooling system dropped a nugget)

[Typhoon]

I had areally bad welch plug experience the other day on teh Supra. Replaced a ehad gasket a couple of weeks ago, laminated gasket and ARP studs. Had a welch plug fail on me on the way home at highway speeds ona back road.
I didn't catch it on the gauge in time, first warning I had was temp gauge at red almost instantly, then mondo smoke from burning coolant. The steam was hot and fast/concentrated enough that it MELTED the PVC insulation tape off the ground wires bolted to teh intake manifold, and engine heat MELTED the spark plug boots to the plugs. I had to destroy some boots/leads to get them off. No coolant in the oil or vice versa.
However, would you believe it still has good compression numbers (cold), ran with a glass smooth idle once it cooled down and has good oil pressure still.
I have my fingers crossed, but will not know if it survived till I fix the welch plug and run it back up to temp. I am saying 50/50 chance, but I think I am optimistic.
I was very cautious with the head gasket swap, lots of time went into it, I even replaced one welch plug that looked dodgey and had been weeping a little! Should have done them all I suppose.
I don't really want to yank the head again within a month. I think I'll be paying someone this time.


Regards, Andrew.

 

[Datsrboi]

Ouch.. Maybe I should pay a shop to do the work when I get my car back. Do not want to go through this.

 

[fiyota]

What is a welch plug? sorry for the noob question.. like a freeze plug? To stop the block/head from freezing in winter?

 

[Jaguar_5]

I'm pretty sure it's welsh plug, and yes, thats the freeze plugs, except it doesn't stop the block from freezing, it stops the block from cracking if you don't have enough antifreeze and your coolant freezes

 

[LilMissMkIII]

Andrew, Sorry to hear mate!

I was really hoping to catch a glimpse of this beautiful car when i was down your way this past weekend!

(By the way, i am Kristel from sf.com.au )

Fingers crossed for you that all is ok!!!!

 

[Typhoon]

I am hoping it's O.K, just tried to retorque the head studs, none would budge at 80 ft lbs, so that's a good sign at least.
Can't wait to get the spark plugs out and have a look( had to remove valley cover to dig old plug boots off the plugs!). Still need to get a vacuum in there, broke the insulation on one plug with the screwdriver.
Compression even and good across all cyls too.:icon_bigg

Regards, Andrew.

 

[fiyota]

I'm pretty sure it's welsh plug, and yes, thats the freeze plugs, except it doesn't stop the block from freezing, it stops the block from cracking if you don't have enough antifreeze and your coolant freezes

ahh yes, thanks! ya that is what I meant.. when the water/coolant freezes it allows for it to expand by those plugs coming out... should have worded myself a little bit better :3d_frown:

 

[Typhoon]

Actually, welch or freeze plugs are there for the sand casting process. The holes allow the sand (or other forming material) used to form a mould for the block to be removed after the block is cast.

Regards, Andrew.

 

[Jaguar_5]

That would just be a secondary function imo, they are called freeze plugs, aren't they? :biglaugh:

 

[Typhoon]

A photo of a plug from this engine:

What do people think of it? I reckon it looks OK considering, at least it hasn't melted or gotten too hot, which is a bit strange. I wonder if the ECU dumps fuel into teh engine when it gets too hot?

Regards, Andrew.