A real stumper GM 305 :(

Thanks for the quick reply Bobo! I'm gonna change the pump this week and see what happens. This pump has always made a very slight knock that has driven me crazy anyway and like you say, it's time for a replacement before it dies in the middle of February when it's 10 below outside!!

I'll let you know how it works out!

psycho

4 years???? Must be a cheap pump... I have a 94 with factory pump/ 128,000 miles on the 4.3 and a 95 with 98,000 on a 350 with factory pump Both tight and no leaks, if your getting 4 years on a pump you might want to check the belt tension on driven items.

Funny, I had about the identical symptoms on my '86 Buick Century, 3.8 liter (231cu. in.) V6. I just ignored it. After a couple of thermostat changes over a few years (no water pump change, no holes drilled in thermostat), it went away by itself. I'd say the wild temp gage fluctuations are definitely due to air pockets in the system, though like you I have no idea how they got there (or why they don't anymore).

P.S. I'm still waiting for ANY ideas on my EGR (?) problem

4 years and about 150,000 miles. It's the mileage, not the time and like I said, better safe than sorry especially since it takes me less than 1 hour to change and cost less than $50.00. One way or another I have to fix the problem and this is the last piece on the puzzle.

One of the reasons my car has 310,000 miles on it, does not burn an ounce of oil and still has the original engine and tranny is because I try to fix little problems before they become big problems. I also change the oil and filter every 3k miles and use Castrol GTX and a Wix filter.

psycho

Borg Warner pump I believe. There is about 150,000 miles on mine. See my other post.

psycho

1. I'm having a problem with the car and this is the last piece of the puzzle.
2. He didn't say replace it every 4 years, he said in this case it might be a good idea. Maybe the pump had a defect in it. It also has over 150,000 miles on it. It's more the mileage than the time.
3. Guess when it's going to "fail to work"? Yep, on 4th of July weekend in 100 degree heat while you are stuck in traffic. And when you see the bill for the fried engine, towing and the mechanic who knows you are stuck out of town and is going to take you to the cleaners, that's when you will be shocked! I see cars stuck in NYC with steam coming out of them all the time. I'll bet they were waiting for parts to fail before they replaced them as well.

On my car it takes less than 1 hour, costs less than $50.00 and might just fix my air pocket problem.

For me it's worth the $50.00.

Would I routinely change a water pump every 4 years?

No I wouldn't.

Would I routinely change one with 150,000 miles on it?

If it was easy and relatively cheap I would certainly consider it because it is a mechanical device and it will most definitely wear over time.

I change my hoses every 3 years or so anyway.

psycho

That's how I understood BoBo's post. Here's a quote "They aren't a lot of money, and if it's 4 yrs old, it should be due for a failure pretty soon.....Bobo" I get from that that he's suggesting replacement every 4 years. I don't put NEARLY the number of miles on that you do, maybe 15,000 a year if I'm lucky. I got this truck in July 98 with 60,000 on the clock, it now has 114,000 on the clock.

My father is that way, even if it shows SIGNS of imminent failure, it's not getting replaced till it fails.

Mine are originals, 10 years old. Cooling system still works perfectly, so they aren't getting changed any time soon.

It's too nerve racking for me wondering when / if the thermo is going to spring open :)

Do you have a google link? I'll take a look.

psycho

Yea I see your point. My experience with GM big/medium block V8's is that corrosion sets in and the pump, generally the impeller, usually lets go before it starts to show any signs through the weep holes.

However, all of these beasts are different!

I have a friend like that!!

My father always said "if it ain't broke, don't fix it!!" I'd take a look at the hoses though, because the rubber decays over time. Unless you have the silicone hoses used in the LT-1s and so forth.

As for the pump, keep an eye on it and look for weeping or noise.

psycho

Pump is 4 years old, replaced as a result of an accident. Hoses do seem fine, don't look deteriorated or anything, and I use no chemicals on them.

Well they can laugh all they want Bobo, but your advice to replace the water pump fixed the problem!

I put it in this morning, filled the system and put in a normal thermostat without a hole drilled in it and the car seems fine.

FWIW the old pump seems ok but the impeller shaft has a little more play in it than the new one. After 100,000+ miles I would expect that. The shape of the new impeller is a little different as well.

Thanks again for the advice!!

psycho

Go to "Advanced Groups Search". Put "Faqgb.54539$ snipped-for-privacy@nwrddc03.gnilink.net" (without quotes) into the "Message ID" box. Click the "Google Search" button.

Thanks.