Chevy & GMC Vans

peter wrote:How does a pump "not pump right"? Unless the impeller is loose on the shaft....

well the 'loose on the shaft' part was what I was thinking... especially since this squeal started. i have seen it before on internally mounted pumps. the impeller, after all, is usually only pressed on the shaft

i know the squeal isn't the two other pulleys, as i replaced both of them only a month or two ago

(i'm sure you'll get your chance peter... one day)

It's fast becoming my reason to get up in the morning

I'd be surprised if the impeller wasn't pressed onto a splined shaft. Anyone?

I did hose out the fins front and back of the rad before driving it this morning. no change, gauge still peaked just under 3/4 before falling to just around/over half.

I'm taking the 93 into work today and I'm going to run the tester on it to see if the alternator is charging normally. I'm also hoping that one of our many tech customers comes in for 'side job' parts today and can take a listen to pinpoint if it is the pump.

man, if it wasn't for these van's think of all the spare time I'd have to get into trouble

ran the test on the alternator and it's charging 100% normal. oddly enough the squealing has gone this morning.. stupid van!!

If I where you,I wouldn't drive it until I fixed it.All too many threads of the shaft coming out to water pumps seizing and breaking off to blown head gaskets.The 4.3's seems to be very forgiving,but....It is always cheaper to fix before serious damage happens.

Just trying to be a buddy,

Gar

thanks Gary. if i still commuted with the van I wouldn't be driving it. 4 - 5min one way to work doesn't have me too concerned.

update on this also: i got a new waterpump in from my warehouse. for how cheap it is I'd rather change it and see if it resolves the problem. if not .. I'll have a spare pump or a nice sized paperweight.

Honestly, I couldn't care less about the "3/4, then swings back down to half" part. So what if it goes to 3/4 before the stat opens. It's not even close to red-lining. The only reason I'm worried is because you claim that the average operating temps are higher than before.
Try swapping out the stat again. I know it seems ludicrous (Google it ), but it's the only thing that makes any sense as far as the temps getting up that high before the stat opens. It's either the stat, or your gauge is off!

peter wrote:Honestly, I couldn't care less about the "3/4, then swings back down to half" part. So what if it goes to 3/4 before the stat opens. It's not even close to red-lining. The only reason I'm worried is because you claim that the average operating temps are higher than before.
Try swapping out the stat again. I know it seems ludicrous (Google it ), but it's the only thing that makes any sense as far as the temps getting up that high before the stat opens. It's either the stat, or your gauge is off!

Peter-the noise doesn't.Idler pulley,A/C,water pump.etc does.

peter wrote:Try swapping out the stat again. it's the only thing that makes any sense as far as the temps getting up that high before the stat opens. It's either the stat, or your gauge is off!

ah yes... I think that I might just be doing that. however, I managed to catch a tech just before we closed today. he's loaning me his scanner for the weekend. the noise he quickly diagnosed as belt noise, not a pulley, bearing or impeller shaft noise.
he is leaning towards the gauge sender reading improperly. he scanner will tell us exact temps and at what temps the stat is opening. if the gauge is 'off' and the stat is actually opening at 195 - 205 it's the sender to the gauge. if it's opening 210 - 225 then it's the stat itself. beats draining and swapping it out again only to find I didn't need to.

if this scanner actually works I might ask for one for fathers day LOL

and not to jack my own thread.. he said the scanner will also give me a much more specific diagnosis on my hesitating 99 while driving... two vans .. one stone ..err scanner

crash wrote:

peter wrote:Try swapping out the stat again. it's the only thing that makes any sense as far as the temps getting up that high before the stat opens. It's either the stat, or your gauge is off!

ah yes... I think that I might just be doing that. however, I managed to catch a tech just before we closed today. he's loaning me his scanner for the weekend. the noise he quickly diagnosed as belt noise, not a pulley, bearing or impeller shaft noise.
he is leaning towards the gauge sender reading improperly. he scanner will tell us exact temps and at what temps the stat is opening. if the gauge is 'off' and the stat is actually opening at 195 - 205 it's the sender to the gauge. if it's opening 210 - 225 then it's the stat itself. beats draining and swapping it out again only to find I didn't need to.

if this scanner actually works I might ask for one for fathers day LOL

and not to jack my own thread.. he said the scanner will also give me a much more specific diagnosis on my hesitating 99 while driving... two vans .. one stone ..err scanner

Very cool.Be sure to post what you find.

Remember ... the scan tool will only report what the temp sending unit is telling the 'puter.

If the sending unit has a resistance of say 400ohms then the 'puter will report whatever the temp tables say 400ohms equals to in degrees no matter what the actual temp is.

Some engines have a gauge temp sending unit AND a 'puter temp sending unit.
Some engines use the same temp sending unit for BOTH the 'puter and gauge.

The factory troubleshooting chart will usually list the various temps to ohms table or just the hot and cold numbers.

Have you used a laser/infared temp therometer yet?
http://www.harborfreight.com/cpi/ctaf/D ... mber=96451
They are usually on sale for about 1/2 price.

Very good, Grasshopper. You have done me proud...

On my 97, the 'puter had it's own temp sender, other than the one that ran the gauges