Driving along, smelled coolant & temp gauge started to rapidly spike.
Stopped ASAP and after engine cooled down, added coolant but it's just pouring out and dripping off the oil pan/flywheel area.
Already had replaced hoses, heater hoses, water pump , coolant elbows and LIM gaskets in past year.
Radiator is nowhere near the leak--so freeze plugs seem like the only things left.

Never replaced freeze plugs and know even less about them.
I believe there are 2 expansion plugs on the starter side and I am guessing 2 more on the firewall side.
Are there also others; maybe 1 or 2 on the flywheel end of the engine?

What are the best replacements?
Best way to replace?
All should be replaced at same time?
Difficulty with engine in car?


Thanks, in advance.

its a cast engine so they put sand/wax in the places where there will be a cavity- like cylinders/block. after casting is done, they have to get the sand out - so they make a hole- plug.

yes, depending where its at, it could be a major pain - you could use stop - leak if its not that big.

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

Thanks. Unfortunately for me, it's a huge leak.
If there is a freeze plug behind the flywheel (and IIRC there's one there)--that's the one that went.

Anyone know the easiest way to replace that one? Pull motor? Pull transmission? Just separate the 2?

Does a sealant need to be applied to ensure a leak free job?

fill it, get it on ramps and find the leak - maybe its pooling, then dripping

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

In regards to the difficulty to replace, that is all dependent on where/which plugs it is. If it is the one behind the flywheel, well... It'll be ugly to R&R and you have pretty much guessed the steps.

However, once apart, here is how to replace them. They're pretty easy actually;

general-chat/topic51734.html

_________________


Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
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Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck

Thanks, both of you.

It is the one behind the flywheel.

Do the motor and transmission have to come out or can just the motor or just the transmission be removed?

See my two replies on this thread.
http://www.pontiacbonnevilleclub.com/forum/post401243.html

It would have been so much nicer if they did use freeze plugs.

Thanks, Roadrunner.
If it's common, then it's likely the problem; The coolant just pours out as soon as I start adding it.

Would this put coolant into the oil or is it like head gaskets in that symptoms depend on what part of the gasket blows?

Am I correct in thinking that the intake has to come off, after the engine is pulled, in order to remove the rear cover and replace the gasket?

Are there also freeze plugs on the rear of the block?

It may be possible to have this gasket leak water in oil but I have never heard of it or have seen any posts about it.

Intake does not have to come off. Just pull engine, unbolt flex plate and drop oil pan.
Twice I pulled engine to do it and one time when having transmission work done, the shop let me change it from below while they had the trans out.
Sometimes the bolts are just finger tight so you may want to use tread locker when you replace them.
I always change the rear main crank seal while I'm at it. When bolting cover back up, you have to shift it around so that bottom of cover is flush with oil pan gasket surface.

Pretty sure there are no freeze plugs in back of block.

GM issued an updated cover part number but the only change made was the addition of a step for the rear main so you couldn't drive it in too far. I never had a problem with installing rear main so I never bothered with the new part.
I have the engine from my '00 a sitting around on a stand if you need pictures of anything.

Thank you very much.
Never read about the rear gasket issue and am surprised it didn't make the "Common Problems" sticky.

Any other unlisted common failures that might surprise me?

I'm debating doing the head gaskets, since temps briefly spiked into the "red zone".
Will probably drop in a hardened 4th clutch hub and PCS while everything is out---since I don't relish the task of pulling the engine/trans.