coolant compression test for coolant leak?

What is involved in a coolant compression test for coolant leak? What exactly is it? Does it involve blowing compressed air into your radiator and see where the coolant comes rushing out? After overnight
parking I recently repeatedly see a small puddle of anti-freeze under where the radiator drain plug would be and wonder if its a real leak or just the hose or even leaky drainpip. I left my car at a mechanic for a compression test, and he did confirmed it has a leak on that side. Anyway, I am just curious if this test is in fact blowing air into the system. I suspect it is because now the car stalls unexpectedly at stop signs and it idles funny. The last time this happened was when I changed the heater core or do something that introduces air bubbles into the cooling system. What someone told me is that when you have air bubbles in there it comes times cause coolant flow to stop flowing in some part of the engine causing minor overheat and causing the engine to cut out. Sounds sensible enough.
So now I am trying to drive the car furiously on the highway to bleed out the air bubbles. This car has the coolant reservoir connected to the radiator cap hose and this valved radiator cap allows air bubbles to flow out after driving for a while.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sam Kaan wrote:

No.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sam Kaan wrote:

Oops, my other post was an accident - please ignore it. A compression test and a radiator pressure test are usually thought of as two different things. Compression test usually means hooking up a pressure gauge to a spark plug hole and cranking the engine to read the compression (pressure).
There is another test where the tech applies air pressure to the spark plug hole to see how quickly it leaks off - OR to see if air bubbles out the radiator fill hole. If air comes out the radiator, then that means a blown head gasket and/or cracked block or head.
A radiator pressure test should be done by placing a small hand pump where the radiator cap goes and then pumping up to normal pressure. If it looses pressure then there is a leak in the system.
If your engine cuts out because of air in the system, then there is a major problem and not just a simple drip - unless it dripped out all the coolant.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
If the engine is dying AND you have a coolant leak, I suggest that the coolant is leaking onto the Crankshaft Position Sensor (CKP). GW
py* snipped-for-privacy@texxxas.net wrote:

Sam Kaan wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Geoff Welsh wrote:

Yes, I forgot about that sort of thing. Had a similar experience with my own car: there was a pinhole leak in the rad tank where the hose connects and water would spray on the ign.mod connection when water was under hot pressure AND under acceleration (engine flopped over pulling on the hose).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Where is the Crankshaft Position Sensor on the 2.8L MPFI engine (1988 year)? It has almost been a week and I am still having problems with stalling unless I leave the A/C on, ie. as long as the compressor is on, it won't stall. Although the engine runs rough, and idling seems unstable. I am going to investigate this crankshaft position sensor you mentioned.
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Look for wires going behind the harmonic balancer (crankshaft pulley).
(Unless this a 1988 2.8L in a Fiero...... they still used a distributor) GW
Sam Kaan wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Well no, this is a 1988 Oldsmobile Cutlass Ciera with the 173 2.8L MPFI
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
What is the appropriate procedure to get the computer code from a car that has stalled? Do all instances where the car stall generate a computer code? I keep getting code 12 even when the car stalls and shows "Service engine soon". What I did is when the car stalls I would turn the ignition key to off, short the ADL(spelling?) with a bent paper clip. Turn the car ignition to the on position. After this I hear the radiator fan comes on and the light flash (ON... wait... ON ON) ... long long wait... (ON wait ON ON) ... long long wait ... repeats.
Early this morning I drove the car onto the street with stop and go traffic to see if I can pinpoint exactly what happens when it stalls. This is what I notice. Lets says I am driving at 40km/hr, then coming to a stop sign I start to press on the break pedal. The car would come to a stop, then it would idle high... low... high ... low , then stumbles for a little and cut out. Then I would restart the car, and right after it starts up, it would idle really really high, then a few seconds later the idle would drop down to low normal level. but it would tend to repeatedly rev up a little and drop down and then rev up a little and drop down repeatedly like that. Then I would drive off until the next set of stop lights where the whole procedure would be repeated :)
Of course this is uncomfortable and is a lot of wear and tear on the starter motor. So I get around this by turning on the A/C. For some reason with the AC on, the car doesn't stall as much even though the problem with up/down idling still exists, yes I can hear the high ... low idling of the engine even through the noise from the AC compressor.
Could this be the electric fuel pump that's about to go?? Or a TPS that has some bad spot on it? Or IAC? or Crank position sensor? It would be easy if I can just replace them all and that would eliminate the problem. But low and behold, these parts (sensors) cost a bundle. Its incredible how much these things individually cost.
Car stats: 1988 Oldsmobile Cutlass Ciera Brougham 2.8L V6 FWD, 3 speed automatic, A/C 174296 kilometer on odometer leaking radiator.
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I'd be inclined to say its the fuel filter... i had the same problem with a 92' lumina, it was doing similar things you discribed so i changed the fuel filter in hopes of not having to change the pump and... walla! car runs mint like its brand new.... Obviously more pep now that there is more fuel getting to the engine.
DJ TecThreat
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
No all stalls will set a code, only if it stalled from a sensor cutting out. You will get 12 THREE times before any other codes. They will all come three times, before another code. Honestly, to me, it sounds like a vacuum leak or a failing IAC motor from your long/good description. GW
Sam Kaan wrote:

-- GW - Conservational Ergonomist - note incorrect email address "It's good to yell at people and tell them you're from Tennessee. That way you'll be safe." - Gary Busey
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"This is what I notice. Lets says I am driving at 40km/hr, then coming

No other information needed.
You should get the NON-Related coolant leak fixed however.
Your main problem is a very common one, Torque Converter Lock up solenoid in the transmission. Do a web search for the problem and what it takes to fix it.
You MIGHT be able to troubleshoot the problem by TEMPORARILY disconnecting the harness going to the tranny to confirm that the problem goes away. Do not leave it like this as not only will your revs at highway speed be higher, but the connector will corrode quickly and prevent a lower cost repair when you do get around to fixing it.
David
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Which connector are you refering to? Why will it corode (due to antifreeze?)?

I have heard of the Torque Convert Lockup solenoid causing stalling problems. However i doubt this is the cause for the following reason. When the car stalls I am able to restart it right away. Whereas people who have Torque Converter lock up usually would be stranded on the street (ie. they can't restart their car) for a least 15 minutes or so. Is 15 to 30 minutes cutout the usual things when people have this problem with the TC solenoid? I haven't heard of people whose car stalled because of TC and is able to restart right away, I could be wrong.
Anyway, I totally gave up trying to figure it out and brought the car to my mechanic and I told him what happened and that the only way I can drive around is placing a load on it ie. with the AC turned on. So what he did is adjust the screw on the throttle body to have higher idle. It didn't totally fixed the problem, but stalling has stopped significantly. It seems to happen maybe once every other day instead of at every stop light. And I have learned to notice when it is about to stall and I just switch on the AC, put on some more load and engine will cancel the stalls.
I am not sure what effect having the engine run at higher idle will do in the long run though. I suppose having high idle is the same as your foot on the gas pedal which is what we do anyway when we drive, so hopefully its not a problem.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

So, basically, you paid someone to break your car differently instead of just fixing the problem?

It will waste gas, pollute more, wear the engine and brakes faster, kill the transmission, not to mention the damage being done by the original problem.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That screw is not for idle adjustment, and any movement should be compensated for by the IAC motor. Honestly it sounds like your throttle body just needs a good cleaning. GW
Sam Kaan wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Perhaps you have a intake or other vacuum leak???
Jeremy

--
Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2 /

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
=?x-user-defined?Q?py snipped-for-privacy@texxxas.net?= wrote in message

I forgot to mention also that. It idles really funny. The engine seems to idle all over the place. High ... Low... High ... Low ... and then the engine cuts out. I can drive for a block or two and the engine will cut out as soon as I change slow the car down like for example at stop lights. I have no problem if I keep the foot on the gas pedal, its only when I put it on the brake to slow down the car. Then the engine would idle High... LOW... High ... Low... and it cuts out.
Right now the way I reduce the problem seems to be to turn on the AC at Max or Normal or Bi-Level. It seems as if its not a problem when the engine has a load place on it. Then the engine doesn't cut out as often, although it does it once in a while. I just don't know why. Its a GM 2.8L front wheel drive, automatic, with AC, and have 174000km on it.
Like I said, the last time this happened was summer 2002 when I had swapped out the heater core.
Its very mind boggling, I am going to just keep the AC on for a while and keep driving to see if the problem goes away.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sam Kaan wrote:

That could be a number of things. I would check for vac. leaks, TPS, MAF, MAT, etc.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sounds vacuum related to me too, sorta, see if it goes away with just the AC on or if it also goes away with the VENT on without AC. If both, then vacuum problem. If it's only when the AC compressor is engaged, then it's related to electronic throttle control or dirt. GW
Pal wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Watch out for coolant leak into the engine. Make sure to check engine for intake manifold gasket leak. Next thing to happen could be a blown engine with broken cam shaft or crank shaft. Search the web for "GM 3.4L engine coolant leak" if you don't already know about this problem.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.