I went to pick up my car yesterday from my mechanic... car was in the shop for an engine rebuild so i had a bunch of stuff done to it while it was taken apart. i told my mechanic i wanted a new water pump, so he put one in... when i went to pick up my car, he told me he would rather not give it to me yet because there's too much pressure in the radiator. The car isnt over heating (anymore), but he thinks the pressure is due to the fact i had my heads ported and he thinks that maybe compression is getting out of the chamber and leaking into the coolant reservoir, causing the pressure to build up over time. the moment i heard that, i thought to myself "thats some bull **** if i ever did hear it"... i started to ask questions and finally got them to admit they put a standard flow water pump on my car when i should have a reverse flow water pump instead. they INSIST that the standard flow water pump isnt what's causing the pressure build up in the radiator, and that it will work fine on my car, but i don't see how a standard flow water pump will work with an engine that's designed to work with a reverse flow water pump. would the wrong type of water pump create pressure to build up over about 20+/- minutes? and not to mention if the car idled for about 15 minutes, it would start to over heat... they fixed that problem by changing the march crank pulley i had on there with the stock crank pulley.... well, actually, i dont think they 'fixed' the problem, i just think they covered it up. what do you guys think? thanks for all your help guys!

 

The impellar is completely wrong if it is for a standard rotation (V-belt) application... Your water flow will not be up to spec and that will cause your overheating, and that will cause excessive pressure (boiling?)... Make them fix their idiotic mistake.. (WP-715 is the correct pump from Advance Auto Parts)...

 

thanks man... i had a feeling it was the water pump, but when i brought it up to their attention, they tried to act like i was wrong... i dunno how they can make such a stupid mistake

 

Sounds like you need to make them fix there mistake, and then find a new shop.

Just out of curiosity, what is the pressure at? 15psi is normal, anything over that should force the relief valve open in the cap and either bleed off the excess pressure or bleed out the excess water.

If the head has a hole in it, it can easily be detected with a 5-gas analyzer. Have them place the probe over the radiator fill, and the exhaust byproducts should be able to be detected.

I doubt that's it though. Sounds like they are trying to shirk the blame back onto your shoulders.

 

my mechanic tells me it's at 18 psi, but i don't know if it's actually more than that or not. i think it's just another attempt for them to squeeze a little bit more money out of my pockets before they're through with me. lol

 

With the stock radiator cap, the cap opens at 16 psi and the excess coolant/pressure is vented to the overflow tank. Is the mechanic stating that you need a new rad cap? It is possible that it is corroded and won't fully open...

However, that doesn't account for putting a regular rotation water pump on a reverse flow setup

 

he replaced the radiator cap too see if it helped, and it didnt... so he replaced the radiator as well but it still did the same ****, so he put the stock one back in.

i had an argument with him today because i told him he needed a reverse flow water pump and he keeps telling me i don't, and what he put on the car is the part that goes on the car... he said he called up discount auto or something, gave them the year, make, model and engine size to the guy, and thats the water pump he gave them. he's convinced it's the heads, so im going to let him take off the heads to replace the gaskets (cuz it's a pain in the *** to do, i might as well let him bust his ***** cuz he doesnt want to listen to me), and if the radiator still has too much pressure, then im going to force him to replace the water pump. he told me today, "there's no way it's the water pump, cuz then the car would be overheating... it wouldnt be circulating the water/coolant if it was going the wrong way"... **** like this pisses me off cuz i trusted this guy with my car and he's trying to squeeze a little bit more cash out of my pockets before he gives me back my car.

the model number to the water pump is GMB130-1620... i tried calling up the manufacture, but they said that model was discontinuted because it wasn't selling... i tried looking online but i couldnt find any information as to if the water pump is a standard flow water pump or a reverse flow water pump... i was thinking maybe my mechanic said standard instead of reverse flow because he doesnt speak much english and didnt understand what i was asking... if anyone has any idea if that water pump is reverse or standard flow, please reply and let me know. thanks a lot guys

 

This is too wierd. Why the hell would you replace the radiator for a bit too much pressure? The radiator cap is the safety valve. Is is not opening?

Also, since he refuses to put in the correct water pump (assuming the engine is running the stock serpentine setup and the belt is routed correctly), then that is still your problem. And how do you deal with it? BY HAVING HIM PULL THE HEADS TOO? WTF? Just so he can soak you for more labor/parts? What exactly are you thinking here?

Also, you already have a communication gap with this guy since he doesn't speak English well.

Please tell me there is some master plan that I am unaware of...

 

he's pulling off the heads, and it isnt going to cost me **** because it's his fault he has to pull the heads. i know the problem with the car has nothing to do with the heads, but if he needs to take them off to realize i was right about it being the water pump, then i'll let him take it off.

i speak spanish pretty good, so i was talking to him in spanish most of the time... but when i talked to him about the water pump, i talked to him in english because he understands english too, he just doesn't know a wide range of words to use, so he talks to me back in spanish. i dont know if he misunderstood me, or if he did understand me perfectly and him telling me the water pump is a standard flow water pump was the truth... i just wish my mechanic would be honest with me and stop trying to blame other ppl for his mistake... grr

 

As long as you don't have to pay him for taking the heads off again...and he doesn't keep charging you labor for work he has already down...either in dollars or pesos...you would be ok.

Mechanics hate to be told by the lowly customer that they are wrong

 

i told him to his face he got the wrong water pump, and he says he didn't... i don't know how to convince the SOB that he got the wrong water pump, but w/e... when he takes out the heads, replaces the gaskets and figures out that he did all that for nothing, then i think he'd be forced to change the water pump, lol

 

Searched where and who did you call?!? Jeez!

TRY THIS!

Surprise! It's the right waterpump. "93-88 6,8CYL CHEVROLET 262 (4.3L), 305 (5.0L), 350 (5.7L)"

Now you need to tell him to his face 'I'm sorry!'

Why not tell him something constructive, like say, 'Do a compression and leak down test before ripping off my bloody heads', or something to that effect.

 

Seriously, you need another mechanic.

Before he removes the heads or anything crazy, demand a correct water pump. Even if he's eating the labor costs, it'll save time getting your car back on the road.

Like I told you in your other post, the easiest way to tell if it's a standard rotation post is to look for the threaded accessory bosses on the right side of the pump.


Here's a standard rotation pump and you'll see the difference.

 

REVERSE rotation pump:

 

thanks for the help red devil... i appriciate it

lol, i really wasn't wrong to assume they got me the wrong water pump... they told me it was a standard flow water pump, and thats what i went on. now that i know it's a reverse flow water pump, i wonder what's causing too much pressure in the radiator even though the car isnt over heating

 

IIRC, they design an underdrive pully set to spin the water pump at stock rpm so the motor doesn't overheat. If they left your other underdrive pulleys on, and only changed the waterpump pulley for the stock one, it's possible that the waterpump is now being overdriven. BUT, the cap should still be "correcting" the pressure problem. Have them pressure test the cap to make sure it's not defective new.

The system is pressure tested at the same point that the cap sits, so any excess pressure is sitting right under the cap. The cap should be able to vent it out to the catch can.

Could be mistaken, but it's something else to look into.

 

they put the stock crank pulley on because they said the smaller crank pulley wasnt spinning the water pump fast enough. i guess ill have to buy the water pump pulley later when i put the march crank pulley back on later.

yeah i think the cap was replaced with a new one, but gave the same problem... they're trying to tell me that the heads have a crack in it, and that compression is leaking out and causing the building pressure in the radiator... i think they didnt seat the heads right, or it's one of the head gaskets, because honestly, i think they're trying to put the blame on the guy who ported my heads rather than on themselves or the machine shop who seated the heads on the block

 

 

i feel like a burn out sorry if i frustrated anyone with my stupid post, lol, but i appriciate all the help i got

 

Sounds to me like you should probably just pick the car up from that shop, and take it to somebody you can trust a little better; or learn to fix it yourself. Which REALLY isn't that hard. You can get alot of help here if you can give straight answers to questions that are asked.

This entire thread reminds me of an interesting thing. Ever hear of how doctors in the Arab world traditionally had to treat women? Their customs do not allow a male doctor to examine a woman's body unclothed, or even to approach her if she's sick with certain things; so the doctor is obligated, literally, to stand outside her tent and diagnose her without seeing her or even talking to her. He has to ask her female family members or servants or whoever to go in the tent and look at something or aske her a question, then come back and tell him what they find out; and so forth. That's about how this post reads. You don't have a clue what we're asking, or what the mechanic is telling you; you just kind of keep going back and forth getting confused, and meanwhile the doctor isn't finding out what's wrong with the patient, and the patient is dying.

Get a new mechanic.

 

Not stupid, but really, if there may be an issue with a head gasket, you usually diagnose it with a compression and leak down test.

I think RB nailed it. You may want to pick up a haynes and chiltons and familiarize yourself with the workings and lingo that you are, hopefully, going to be using yourself soon.