Help, can't get water pump off

[Mastiff]

This is for the CUCV. All the bolts are out, but the pump is stuck badly to the block (or backing plate?). I've hit it with a big hammer, pried where I could, with no luck. The seal did break slightly when I was prying once, but not enough to get a screwdriver under there. I don't want to booger up the mating surface too much anyway. Ideas?

The pump is trash, so I don't care about damaging it, if it matters.

 

[diesel4me]

6.2 diesel ?...

I'd make sure you have all the bolts out--not hard to overlook one..
Sometimes RTV sticks really good,but it shouldn't take much of a whack with a hunk of wood to break the seal and get it to come off..

After looking at the amount of work it takes to replace a water pump on these engines (and perhaps still ending up with a coolant leak into the crankcase ,I hate any engine that has this design),I think if my 6.2 ever needs a water pump,that might be the final straw,and I'll replace it with a small block...those are so easy,4 bolts and its off..

Here's a illustration that might help you..

 

[Mastiff]

Yeah, 6.2. Man, sure think I have them all off. I have one for every hole on the replacement pump. I'm going to double check against your diagram though.

 

[rampage]

Use the same trick I use for prying off diff covers - a small putty knife and tap it in with a hammer all the way around.

 

[diesel4me]

Someone may have used Indian Head Gasket Shellac or "The Right Stuff" RTV on the pump & gaskets--both of those can be tough to break the bond once they set up..Watched my friend struggle to remove a diff cover that had the Right Stuff used on it,he had to pound a putty knife thru the RTV and he actually bent the cover trying to peel it off..you hardly need bolts with that stuff!..

Once I used the Indian Head stuff on a leaky thermostat housing & upper radiator hose on a 67 Impala ,283--two years later I had to replace the thermostat & upper hose,I broke the water outlet housing trying to pry it off using a hammer handle in the hose fitting--after using the hammer & chisel to chop away the upper hose,it was like it welded itself to the outlet...stuck so good to the intake manifold one ear snapped off--it was a die cast part,I bought a cast iron one to replace it..but it didn't leak a drop the 2 years since I gooped it with the shellac..

 

[Mastiff]

The answer is that on a 6.2, there is a backing plate (timing gear cover) mounted to the block, and the water pump is mounting from behind to this plate. The plate has to come off to get the water pump off. We bent the plate pounding on the pump like fools.

 

[TJ1978]

Welp, now ya know/

 

[rampage]

The answer is that on a 6.2, there is a backing plate (timing gear cover) mounted to the block, and the water pump is mounting from behind to this plate. The plate has to come off to get the water pump off. We bent the plate pounding on the pump like fools.

The diagram posted actually shows this.
Did you try finding a ‘how to’ video on YouTube? That’s what I do when doing a repair on friends’ vehicles that I’m unfamiliar with.

 

[Mastiff]

Yeah, totally my fault. One guy on-line was talking about removing the plate, but someone else said he just took it off. I heard what I wanted to hear...

 

[diesel4me]

What a retarded setup...having bolts from the back side of that plate holding the pump,in addition to several on the outside...nothing like making it more difficult to fix,and increase the chances of coolant leaking into the crankcase.....
I have not had to take a water pump off a 6.2 yet--if I had and known about those bolts behind the plate,I'd have told you..

Buick and Olds ,and Caddy engines are similar...Ford 460's too..they use long skinny bolts that corrode away and like to snap off in the block,because they pass thru a thick casting on the water pump & timing cover...piss poor design..

I've said before I'd rip the 6.2 out of my truck and never put it back in if it needed a water pump or injection pump...

This kind of seals the deal...I put up with it for 16 years,that is long enough..time for a gas engine that actually starts 90% of the time below 40 degrees and is a lot easier to deal with,and gets nearly the same mpg,when the water pump starts leaking,or the IP goes south..

 

[Mastiff]

Yup, pretty annoying. The pump came with a gasket, but it doesn't help the fact that that giant plate can leak against the block anyway, both coolant and oil. It occurred to me too that if one of the bolts holding the pump on ever back off, it would fall into the timing gears.

One of the bolts through the pump penetrates into the coolant passage in the block and is a potential leak source. I just gooped some RTV on the threads before putting it in. Was that the right choice, or should I have used something else on those threads? It hit me that the RTV needs air to cure. I drained the coolant as much as I could, but it's not exactly dry in there. I can still change my mind since the coolant isn't filled yet.

BTW, is there a good way to capture coolant for re-use when draining? The petcock on the radiator has no way to attach a tube, and is right up against the fender anyway.

 

[diesel4me]

I've used RTV on exhaust manifold bolts on 318 and a 413 Mopar V8 before and they never let coolant escape (the bolts go right into water jackets in the heads)..Permatex #1 or Aviation Sealer or Indian Head might have been a better choice,but I used what I had..

I thought about that too,a WP bolt rattling loose behind that plate,and getting lunched in the timing gears,probably destroy the whole engine & IP at the same time..the crank would probably snap too!...

As for the petcock,the only thing I could suggest is maybe pulling the lower hose off to drain the coolant might allow you to catch more of it,but most likely it'd just gush all over the frame & body metal and be hard to catch in a drain pan..
Once it was drained,you could put a better petcock in the radiator with a hose nipple,or an elbow and piece of 1/4" pipe to put it in a better location..

I have siphoned the coolant out of some vehicles that had that issue,but you cant get 100% of it out that way,but most of it..

I don't like to rag on the 6.2's,because I cant bitch about how much mine has taken as far as "abuse" and not failed yet,but GM could have done a lot better when they designed them..they were not designed with the poor mechanic in mind ,that is for sure..

The location of the lift pump majorly sucks,right in line with the frame---ditto for the exhaust manifold bolts..may as well lift the engine off its mounts to replace either of those items..
--the WP is a major undertaking compared to a SBC or BBC,the fact coolant can get in the crankcase behind that plate sucks too--and the fact they have their issues with cold starts,"swelled" glow plugs,and like to eat starters (or snap the bolts or the block casting off !),on top of the weak crankshafts,I am not a huge fan of them..plus they dont really have much power,just torque..

They started off with some good ideas--the 4 bolt mains,double roller timing chain,roller camshaft--then ruined it by using a weak cast crank....

They would have been a good candidate for a lighter car like a Nova or Camaro,Chevelle,Impala,but for a truck they should have made a better more "medium duty" diesel,preferable an inline six like some Isuzu box trucks had..

 

[imiceman44]

The answer is that on a 6.2, there is a backing plate (timing gear cover) mounted to the block, and the water pump is mounting from behind to this plate. The plate has to come off to get the water pump off. We bent the plate pounding on the pump like fools.

Sorry I didn't see this post until today, I could have saved you the hassle.
I had a similar incident on a CAT c12 water pump, I banged a little, enough to realize there must be a couple of bolts left.
They were 6" long bolts from back of the accessory box iirc.