Compression Testing

[LVNeptune]

96 Yukon

Noob to vehicle maitenence, etc. I am about to buy a compression kit tester from amazon

http://www.amazon.com/Actron-CP7827...2BRS/ref=sr_1_1?ie=UTF8&qid=1327352459&sr=8-1

What kind of spark plug removal tool do I need to buy to do this? I am guessing 18MM.


Also, everything I read talks about disconnecting the car from starting

http://troubleshootmyvehicle.com/gm_compression_4.3L_5.0L_5.7L/gm_cylinder_compression_2.php

Step 3 "The Ignition System has to be disabled and this can be accomplished by disconnecting the Ignition Coil or the Ignition Module."

How would I go about doing that?

I have a sinking suspicion that the car I just bought from a private party actually has a blown or leaking head gasket but the oil looks fine and the coolant "seems" ok, although it was low (the coolant that is).

Thank you.

 

[LVNeptune]

No ideas?

 

[SunlitComet]

5/8" plug socket. remove all plugs. block throttle wide open. and unplug the multiconductor connectors for the coils and driver. attach the gauge. crank a few revs and observe readings. Please report results back here for interpretation.

 

[LVNeptune]

It should be here later today.

I looked up the term "block throttle wide open" which basically means floor the gas pedal...People don't seem to recommend literally to put a brick on it.

What are multiconducter connectors for the coil and driver?

 

[Ceejkay]

yeah do not put a brick in there, petal to the floor... and hes talking about unplugging the black box with 2 wire bundles going to it on the right hand side fender hump..

 

[LVNeptune]

The one's that are labelled white and black iirc?

 

[SunlitComet]

NO! I meant to disconnect the attaching connectors on coil and driver right next to it. but you can leave the single conductor spark wires on the coil and cap.

 

[LVNeptune]

Well I didn't see that message before I went to start, disconnected white and black and the truck wouldn't turn over or initiate spark so that did it.

Unfortunately there is absolutely NO WAY I can get to the two firewall side spark plugs on each side without hurting myself so I can't even do this properly myself.

I had a friend helping and he couldn't help me very long but I tested the two on the front driver side and those were 150psi. Obviously doesn't help without doing the rest. I think I am going to pay someone.

I am quite surprised noone mentioned the issue with dexcool eating the intake manifold gasket issue and that was probably my issue. I do NOT see coolant leaking anywhere I am parking but it is going through coolant. I do not see it on my dipstick either.

Way too big of a job for a chump like me so I need to take it in.

I am going to have a compression test ran on the engine fully first then the radiator. If the radiator loses compression is it 100% going to be the intake manifold? Thanks.

 

[SunlitComet]

50psi is good. hope it it all around. I myself have never seen proof that dexcool eats gaskets unless the stuff was contaminated. no pressure in raddy could mean a thermostat stuck closed or faulty raddy cap.

 

[LVNeptune]

I hope the "50 psi" you posted was a typo because I had said 150psi

Class action lawsuit should be proof enough

http://www.handymanlyness.com/archi...anifold/GM_truck/gasket_replace_99_Jimmy.html

This LOOKS easy enough but this would take way too much of my time. Definately worth it for me to pay someone to do this.

Also, I still can not see where the coolant is leaking from so it must be burning up before it hits the ground when I'm driving the truck.