anyone who has ever done a compression check, please come in here, also coolant ?'s

[cam98aro]

hey guys, i think i may have a bad head gasket, because im loosing coolant

can anyone give me the psi you got for the test, and also, how hard was it to get to the plugs in order to do the test?

also, when you guys take your rad cap off, how far below the cap is your coolant, with a cold engine? i have checked mine recently, and it was about 1" below the cap.. but i could have sworn that it used to be almost directly under the cap (although i have been checking it when it has been below 32F so it might just be contracting in the rad)

about once a month, i will fill the overflow to full cold, and when i check it, it will be at the very bottom of the dipstick

[EarlR]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

I've yet to run a compression check on my Camaro, but the pressure reading is not as important as the variation between cylinders and the two banks. If you see a large (10+ psi) variance between cylinders that is a bad sign. An educated guess would put the pressure in the 170 - 180 psi range, but don't get too hung up on the numbers.

Also, remember to warm up the motor before running the test (not too hot - don't want to melt/burn things), and to hold the throttle open when crank the engine.

[cam98aro]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

I've yet to run a compression check on my Camaro, but the pressure reading is not as important as the variation between cylinders and the two banks. If you see a large (10+ psi) variance between cylinders that is a bad sign. An educated guess would put the pressure in the 170 - 180 psi range, but don't get too hung up on the numbers.

Also, remember to warm up the motor before running the test (not too hot - don't want to melt/burn things), and to hold the throttle open when crank the engine.

yeah, i understand, i just wanted to get some baseline numbers :cool:

[bigbrian442]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

I've yet to run a compression check on my Camaro, but the pressure reading is not as important as the variation between cylinders and the two banks. If you see a large (10+ psi) variance between cylinders that is a bad sign. An educated guess would put the pressure in the 170 - 180 psi range, but don't get too hung up on the numbers.

Also, remember to warm up the motor before running the test (not too hot - don't want to melt/burn things), and to hold the throttle open when crank the engine.

10% not 10 PSI.

[eazy_e6996]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

i got 180 on mine tested it last week and it still runs like hell

[flamingchicken]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

I did a compression check about 5 days ago because I had the intake off so i figured if I had it that far I might as well check to see if I needed to pull the heads. I had two low numbers, so I took the heads to get worked. Turns out they were cracked in between the seats on the two low cyls.
Here are the numbers:
1-190#
2-170#
3-180#
4-135#
5-150#
6-185#

Here is how I did my check. Since I had the intake off and fuel rail off as well, I pulled the fuel pump relay as to not have gas all over the place. To be able to get clear and acurate numbers I pulled all of the spark plugs too. As someone stated already, the lowest number should not be below 10% of the highest number-

190/10%= 19,
190-19=171
171 should be my lowest number. As seen above mine was 135 so I pulled the heads.

As far as loosing coolant, that is why my motor is apart in the first place. Damn intake gaskets were leaking. Mine was leaking where the plenum meets the manifold, and i had oil on top of my manifold (that could have been valve cover gaskets.) My car overheated bad and the temp gauge read good, I didnt know it till i smelled the smell, and apparently that was too late. Lemme know if you need anything else.

[cam98aro]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

I did a compression check about 5 days ago because I had the intake off so i figured if I had it that far I might as well check to see if I needed to pull the heads. I had two low numbers, so I took the heads to get worked. Turns out they were cracked in between the seats on the two low cyls.
Here are the numbers:
1-190#
2-170#
3-180#
4-135#
5-150#
6-185#

Here is how I did my check. Since I had the intake off and fuel rail off as well, I pulled the fuel pump relay as to not have gas all over the place. To be able to get clear and acurate numbers I pulled all of the spark plugs too. As someone stated already, the lowest number should not be below 10% of the highest number-

190/10%= 19,
190-19=171
171 should be my lowest number. As seen above mine was 135 so I pulled the heads.

As far as loosing coolant, that is why my motor is apart in the first place. Damn intake gaskets were leaking. Mine was leaking where the plenum meets the manifold, and i had oil on top of my manifold (that could have been valve cover gaskets.) My car overheated bad and the temp gauge read good, I didnt know it till i smelled the smell, and apparently that was too late. Lemme know if you need anything else.

hm, thats interesting.. any real way to diagnose a bad intake gasket?

last time i changed my oil there was a tiny amount of water in the oil (basically the top of the oil had some golden spots on it)

how hard was it to take the intake off? every time i look at the engine i get disgusted because of how hard it looks to even work on.. i have no idea why they would hide half of the engine under the cowl

[flamingchicken]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

Being able to pinpoint the head gasket as the problem is something an actual technician would have to tell you I am just a lowly lube tech.

As far as taking it apart, it was pretty well a breeze. there were two problems that I ran into. That damn rear engine bracket that is on there: my solution, i put a socket and ratchet on there from the top (I was able to get the plenum and intake manifold off without removing that, so they were out of the way) and took a hammer to be able to break it loose. The only other thing that i had a problem with is you need to pay attention to the two plastic elbows that make things hard to pry. I broke both of them. One is somewhere, I forget, Ill find it when I put it back together, and the other is right under where the manifold extends on the front for the plenum.

If you do pull the heads, make SURE to figure a way to keep each pushrod in their perspective places, cause apparently they are different lengths.

[cam98aro]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

Being able to pinpoint the head gasket as the problem is something an actual technician would have to tell you I am just a lowly lube tech.

As far as taking it apart, it was pretty well a breeze. there were two problems that I ran into. That damn rear engine bracket that is on there: my solution, i put a socket and ratchet on there from the top (I was able to get the plenum and intake manifold off without removing that, so they were out of the way) and took a hammer to be able to break it loose. The only other thing that i had a problem with is you need to pay attention to the two plastic elbows that make things hard to pry. I broke both of them. One is somewhere, I forget, Ill find it when I put it back together, and the other is right under where the manifold extends on the front for the plenum.

If you do pull the heads, make SURE to figure a way to keep each pushrod in their perspective places, cause apparently they are different lengths.

they are different lengths? that sounds pretty weird

im hoping that its not a head gasket.. usually on an engine, when i pull the heads, i cant help myself from wanting to rebuild the engine.. it seems pretty pointless to tear a high mileage engine down that far only to keep the stock bearings/etc in IMO

ill have to see how much money i can save up, and how long i can get away with this loss of coolant, i will either swap an ls1 in, or a carbed 302

edit* only if it actually is the head gaskets.. i have no problem doin the intake gaskets.. also, is this the LIM gaskets?

[flamingchicken]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

302? ford?

[cam98aro]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

302? ford?

no, chevy

[flamingchicken]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

i thought chevy only made a 302 for one year, 1969...

[cam98aro]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

i thought chevy only made a 302 for one year, 1969...

they made it from 67-69

[flamingchicken]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

cool. if you do that, let someone see some pics.

[cam98aro]

Re: anyone who has ever done a compression check, please come in here, also coolant ?

cool. if you do that, let someone see some pics.

yeah, i have seen a bunch of people that have done it.. it takes a LOT of fabrication though.. also, i have seen some people removing their windshield wipers to fit the intake/carb

an im not sure how i would be able to get my car inspected, unless i have some "kit car" title