Hello from the UK!

My '88 350 TPI Firebird has started losing water, (roughly, the contents of the expansion tank over a 130 mile journey) and I was told by the highly trustworthy American car repairer I've always used that it's getting out around the core plugs.

As you'll all know, the core plugs are very cheap: they said they'd give them to me free, as well as the antifreeze, but the engine has to be removed to do the job. They said it will take ten hours and would cost £600 for labour charges. In the UK, that's pretty reasonable for ten hours' labour.

I have two problems:

(1) I can't afford the repair in the foreseeable future, as I'm struggling financially since my wife died and

(2) My repairer's chief mechanic - a hugely experienced expert I'd trust with my life - has just died, and they now only have one apprentice, with relatively little experience, to take on this work. That's a disaster for them and for their customers. Nobody in this part of the UK now knows who to trust with repair work.

I don't think I have the skill, patience or equipment to take on a job this complex or physically demanding myself: I'm a bit too old for that kind of work.

Several friends (who don't know anything about US cars) have suggested trying to pour water system leak sealant into the cooling system, but I don't know if this would be effective or if it might be potentially damaging. In any case, it would clearly be a temporary measure, as the chance of a core plug dropping out while the car's on the road doesn't bear thinking about.

Does anyone have any thoughts on whether a cooling system sealant would work in the short term and if so what sort should I use? Having no Firebird would be almost as bad as losing my wife was - it got me through the tough times after she died by cheering me up. I'm sure I don't need to explain that to any of you guys!

 

No way would it do that. I'm sure in a rare instance it might but that is very very rare. I would pressure test system or just get motor hot and look at the freeze plugs on the side of the block with car up on ramps. I bet the seep hole in the water pump is leaking or a loose hose, or something simple. Good luck ......

 

Thanks! I think they did pressure test the engine, and they did assure me there were signs of water leaks around the core plugs. I really don't think they'd try to mislead me, they are a good company and treat regular customers, including me, like friends. But I think they did mention there was also some water getting out elsewhere, and if I recall correctly, the word 'pump' was in there somewhere, so you may well be right about the water pump seep hole. I was a bit overwhelmed by the news that the engine had to come out, so I didn't really take in clearly everything they said.

I'll try to have a look under the car with the engine hot as you suggest. At the moment, I don't even know where to find the core plugs, but I guess the enormous repair manual I have somewhere will show them - I will go to find it!

Is the water pump seep hole a job an old (but somewhat mechanically inexperienced) guy like me could take on, do you think?

Thanks again!

 

I once had a (not sure of the correct term for it) a thermal device in the side of the engine block on my new 84 trans am that started leaking. Anyways a shop removed it and and put in a regular freeze plug without doing a thing to the engine. They aren't hard to remove and replace. just tap them into the block and yank em out then tap new ones in. Most you have to do is drop the front portion of the exhaust.

but like I said you can easily see if the freeze plugs are leaking just get the car on ramps and you will see the freeze plugs on the side of the engine block.

If they are leaking trust me it is very visible.

The water pump seep hole is on the bottom of the water pump snout. You should see signs of a drip on timing chain cover or harmonic balancer. Only way to fix is to put a new waterpump on.

 

There are a total of 8. Some of them are easy to get to; some require .... more serious effort.

They are made of thin sheet steel. They fail by rusting from the inside. Don't bother with "sealer", it will do more damage than good. Pretty easy to see why there's no magic stuff in a bottle that can seal a leak that's 35mm wide, without doing SERIOUS harm to everything else involved. Not really a matter of "US cars" as such, compared to any others; AFAIK every mfr throughout the world has something similar, as a byproduct of the casting process.

Here in the States, those of us who have any sense at all (GM, ARE YOU LISTENING????????), use brass ones when we build motors so they NEVER rust out again. Obviously that requires access to them all.

I'd suggest, find out which one(s) are leaking; see if that's something that can be done without too much trouble. About 4 of them are pretty easy to do in the chassis, 2 nearly impossible, and 2 can be done by dropping the transmission. Problem is, all 8 of them have been subject to the exact same conditions for the exact same length of time and are therefore most likely in the exact same state and will all be about ready to fail at the exact same time; meaning, you can change out just the one today, but the next one will fail in a month, then the next a week after that, and so forth .... until you've done all 8.

What Jeff is talking about was probably a block heater... GM uses plugs with a heating element behind them, immersed in the coolant like an electric water heater for your house, to warm the block. These are sold as an option, commonly in extremely cold climates like central Canada and the US northern Plains states and Alaska. You might have those but probably not since it never really gets very cold on a regular basis anywhere in the UK (like, below -30°C or so) to where they'd be of any value.

If the water pump is leaking, replace it. Yes it is a very easy job; should take no more than an hour or 2. Don't forget to use some kind of non-hardening sealer (NOT silicone) on the threads of the bottom bolt on the left-hand side (curb side in the UK) of the car.