Got a Compression Test, HG or just the water pump???

[TB2K]

I got a compression test today with a result of (starting with the air filter side of the engine) 150, 135, 125, 150 and it held. We could actually see water coming out of the water pump. So how likely is it that it is just my water pump? also is it very hard to do the balance shaft removal while I have the water pump/timing components off or does it need to come apart more?

 

[absolute_DSM]

If the water was coming out WHILE you did the compression test it sounds like you have a head gasket issue. Not a problem, glad you caught it early.

 

[TB2K]

nope no water during compression test, water coming out while it's running, and during cooling system pressure test. Everything seemed fine during the compression test.

 

[tbonitz301]

Your compression numbers are out of spec. Might be time to see what makes that thing tick. Be sure to do a leakdown test first. Sounds to me like you have a waterpump problem that may have made you overheat, and now you need a headgasket

 

[sadc]

Might be your gasket for your waterpump. Since you said only happends while running for awhile. Small little crack can do the trick

 

[TB2K]

So the compression is out of spec? The mechanic said according to his book I was just in spec, and that since the compression didn't leak at all while leaving the gauge on that the HG is good.

 

[Rob10_99]

Spec should be 120psi, but whats a fresh rebuild with stock pistons, 185psi?
Which would you rather have? Most people say anything under 150psi is enough for a rebuild.
Its only going to get worse!

 

[Brutus]

So the compression is out of spec? The mechanic said according to his book I was just in spec, and that since the compression didn't leak at all while leaving the gauge on that the HG is good.

Yes 150 is just in spec, but you had two cylinders that were a good bit lower. Ideally you would want to hold pressure a little over 150. It could be the headgasket, but likely its the rings or valves losing compression. You may want to do a leakdown test or wet compression test to find just where you are losing compression.

Oh and I noticed you said the middle two cylinders were low, so you may actually have blown the head gasket between those two cylinders.

 

[TB2K]

Sorry for my dumb questions, but if it was blown between those two wouldn't the pressure slowly drop? We left the gauge on there for a few minuites and did it a few times per cylinder. I will see if he has the leakdown tool, if not there is a resonable mechanic right down the street from me.

 

[TB2K]

Ok I got the water pump replaced, it was very bad, the discoloration by the weep holes and can feel resistance spinning it. I also replaced that coolant bottle, so now the car is holding fluid and cooling fine. BUT now it idles horribly, once over like 1500RPM and up to speed it's fine. Themechanic said it can't be the timing because if it was off by even one tooth it wouldn't run at all because the valves would be bent. So told me to change the plugs and all, and that he had the battery disconnected for a long time so the computer is re learning. I've changed the plugs and PCV valve no money for wires right now but he is now saying it may be a sensor... the only thing that changed was the waterpump and timing belt and that the car was at a decent angle for about 5 hours. I can't see how a pump can make a difference in idle, the tilt thing can't still be effecting it after 3 days so I thouht it would have to be the timing. What do all you so much wiser than I have to say?

 

[talon187]

if my memory servers me right timing on our cars can be off by one tooth maybe 2 and it will run just it will run like poo

 

[silver bullit]

Do the compression test again, with the throttle open.
Do this with the motor warm all the spark plugs out and no radiator cap on lmk what the results on it

 

[oldman420]

When your water pump seal goes it will pee out the hole at the bottom. Dude sounds to me like a hg, might as well look into arp head studs while your in there.
Do a leakdown first though, just to confirm.

 

[TB2K]

think it's a HG even though I'm not loosing coolant anymore? and it idled just fine when I took it in, just lost coolant like crazy.

 

[My1GLaser]

Unless the mechanic's compression tester is different than most, it has a schrader valve in it that holds the pressure regardless of if it is leaking down in the cc. The ring end gaps would allow the pressure to leak down over time. It is like a peak and hold gauge. At least every one I have ever owned is. Thats why they have that little bleed valve on the hose, because the pressure will stay in there no matter what.

Your compression test is telling me that something isn't right b/w those 2 cyl. Did you take off your rad cap and listen for gurgling during the test?

With those numbers I would say a leakdown test is a must.

You aren't going to bend valves if you are 1 tooth off unless you had major decking done to the head/block. It'll run like crap though.

 

[talon187]

arps and a mitsu 4layer headgasket if you plan on running lots of boost