L98 Water Pump
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
If you want to know about the head gasket then do a quick block test with dye and find out in seconds. You can RENT both the dye and the tester at Autozone with refundable deposit or you can also just buy it. It's like $25 for the tester and about $8 for the liquid dye. Fast and easy.
Last edited by 86PACER; Sep 28, 2010 at 01:26 AM.
Safety Car
Joined: Jan 2004
Posts: 3,759
Likes: 8
But a head gasket also would not make the bottom of the radiator remain totally cold while the top hose is totally hot.
If you want to know about the head gasket then do a quick block test with dye and find out in seconds. You can RENT both the dye and the tester at Autozone with refundable deposit or you can also just buy it.
If you want to know about the head gasket then do a quick block test with dye and find out in seconds. You can RENT both the dye and the tester at Autozone with refundable deposit or you can also just buy it.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
I agree it sounds like a possible clogged radiator. But it looks like to me there are 2 problems. One is a possible clogged radiator. The other is the car is getting to 230 within a minute of a cold start. That shouldn't be happening. It doesn't matter if the radiator is clogged or not with regards to reaching 230 within a minute.
That's more than I would like. He didn't seem to do a "wet" test. I saw 197-200 psi dry across all 8 on mine. I would add a block test with dye.
Safety Car
Joined: Jan 2004
Posts: 3,759
Likes: 8
I agree. But his leak down rate seem to check out fine. #6 compression is low though. Almost a 50 psi difference from 1 2 and 8.
That's more than I would like. He didn't seem to do a "wet" test. I saw 197-200 psi dry across all 8 on mine. I would add a block test with dye.
That's more than I would like. He didn't seem to do a "wet" test. I saw 197-200 psi dry across all 8 on mine. I would add a block test with dye.
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 763
- and to me it sounds like a clogged radiator. if the OP indicated the inside of the radiator looks horrible, i'd just bite the bullet and install a new one - sound like his car needs it anyway...
Thread Starter
Drifting
Joined: Aug 2002
Posts: 1,775
Likes: 125
From: Birmingham AL
Okay, this is what I plan to do. Once I get my new plugs installed, then I will put the front of the car on ramps to eliminate any possible air bubbles in the system. Then I will remove the radiator cap and crank the car. If the coolant on the cap side gets sucked down, then the pump is working. And if the radiator is clogged, then coolant will trickle or not from the other side. I might also remove the thermostat to eliminate the possibility. I ran the compression check in order to make sure that I didn't warp or crack a head and to make sure the head gaskets are okay. Now, I feel that either the pump or the radiator is the issue. A new thermostat will go in because those are cheap. I think that this simple test will tell me if I have a bad radiator or pump without additional tools or a big mess on the garage floor.
Team Owner
Joined: Jan 2003
Posts: 20,304
Likes: 240
From: Summerland B.C. Canada
As stated, a clogged rad and stuck stat, won't come into play for 5-10 minutes of idling, from a cold start.
How can either of those be the problem if the temp reaches 230* in a single minute ???????
How can either of those be the problem if the temp reaches 230* in a single minute ???????
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Drifting
Joined: Aug 2006
Posts: 1,624
Likes: 2
From: Canandaigua New York
There is one other thing that can cause your symptoms.
A crack in the cylinder wall at the water jacket.
When you do a compression test, it's being checked under a 'cold' condition and a leak down test may not show much, if any, pressure loss.
But once you start the engine, the pressure from the 'heated' cylinder can 'force' the crack open causing the water to heat very fast.
I only suggest this because I had a 65 Malibu that had this exact problem.
I even pulled the head (6 cylinder) and couldn't find anything wrong with the casting or the gaskets.
I inspected the cylinder wall and found what looked to be a 'scratch', which of course turned out to be a crack.
This may not be your problem, but it's another thing to consider.
A crack in the cylinder wall at the water jacket.
When you do a compression test, it's being checked under a 'cold' condition and a leak down test may not show much, if any, pressure loss.
But once you start the engine, the pressure from the 'heated' cylinder can 'force' the crack open causing the water to heat very fast.
I only suggest this because I had a 65 Malibu that had this exact problem.
I even pulled the head (6 cylinder) and couldn't find anything wrong with the casting or the gaskets.
I inspected the cylinder wall and found what looked to be a 'scratch', which of course turned out to be a crack.
This may not be your problem, but it's another thing to consider.
Thread Starter
Drifting
Joined: Aug 2002
Posts: 1,775
Likes: 125
From: Birmingham AL
At this point, I'm hoping that the block is a little low on coolant which would expose both temp sending units to air. The air temp would definitely rise that quickly. When I get the car up on ramps and top to cooling system off, hopefully this will change.
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
The radiator doesn't come into play until the thermostat opens. This is at least a few minutes after start. The one minute and 230 degree thing means something is amiss with the motor. To the op, did you do an actual leakdown test or did you just hold the pressure from the compression test? Race motors leak more than 1%. The pressure in cylinder #6 is going somewhere.
Last edited by 383vett; Sep 28, 2010 at 10:27 AM.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
If no sign of H20 in the oil and head gaskets check out then I'd flush the block and hoses - pull/replace the T-stat to see what kind of "gunk" pops out of the cooling system. Might be time for a new pump and radiator as well.
good luck -
Thread Starter
Drifting
Joined: Aug 2002
Posts: 1,775
Likes: 125
From: Birmingham AL
I'm betting the OP needs a new stop watch or he has way way less coolant in the block than he thinks.
If no sign of H20 in the oil and head gaskets check out then I'd flush the block and hoses - pull/replace the T-stat to see what kind of "gunk" pops out of the cooling system. Might be time for a new pump and radiator as well.
good luck -
If no sign of H20 in the oil and head gaskets check out then I'd flush the block and hoses - pull/replace the T-stat to see what kind of "gunk" pops out of the cooling system. Might be time for a new pump and radiator as well.
good luck -
The OP
(myself) likely does need a new stopwatch. I could be way off on the minute to 230 deg. I didn't use a watch, just a guess. Time sure does seem to fly when the temp numbers are rolling up. It could have been 2-3 minutes. I'll have to get a stop watch to make this more scientific. I also think that the coolant is likely low in the block which will throw the temp readings off. The heater core probably weeps a little. Either the water pump is dead or the radiator is clogged. I'm working late every night for the rest of the week so it may be a few days before I can continue to diagnose.
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
You must know that a compression gauge has a pin that releases the pressure. Without releasing the pressure, the pressure only can go up between cranks and does not decrease, hence your 1% or less leakdown. Get a real leakdown gauge and see what is going on. You might find that you have a gasket leak beteen 6&8.
Thread Starter
Drifting
Joined: Aug 2002
Posts: 1,775
Likes: 125
From: Birmingham AL
You must know that a compression gauge has a pin that releases the pressure. Without releasing the pressure, the pressure only can go up between cranks and does not decrease, hence your 1% or less leakdown. Get a real leakdown gauge and see what is going on. You might find that you have a gasket leak beteen 6&8.
Thread Starter
Drifting
Joined: Aug 2002
Posts: 1,775
Likes: 125
From: Birmingham AL
You must know that a compression gauge has a pin that releases the pressure. Without releasing the pressure, the pressure only can go up between cranks and does not decrease, hence your 1% or less leakdown. Get a real leakdown gauge and see what is going on. You might find that you have a gasket leak beteen 6&8.
Could you elaborate a little on what's involved in the leak down test? I am imagining a device with a guage that allows one to pump compressed air into individual cylinders at TDC or when both valves are closed.
Thanks,
Anthony
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
Hi Anthony. A leakdown gauge has two gauges, one to measure the pressure of the air going into the cylinder and the other to measure the pressure of the air leaking out. You need an air compressor for to use this gauge. It is screwed into the spark plug hole with the piston at top dead center and the valves closed so theoretically, the cylinder is pretty well sealed up. Listening to where the air hisses out of the cylinder will give you an indication of where the air is leaking. Someone will soon post a picture of the gizmo. Hope this helps.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Team Owner
Joined: Jan 2003
Posts: 20,304
Likes: 240
From: Summerland B.C. Canada
Get the dye and test for exhaust gas in your coolant.