3800Pro Forums banner

1 - 6 of 6 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
We bought a 1994 Buick Regal with a series 1, 3.8 engine.
We did a chemical combustion leak test that came out positive for combustion gas in the coolant. We repeated the test several times to make sure and with a different bottle of the test fluid.

We tore the top half of the engine apart and sent the cylinder heads off to a machine shop where they were pressure tested and we were told they were fine.

So we got the engine back together including a new plastic upper intake. We flushed the coolant system and re-tested for combustion gas. It came back positive yet again.

We also had the shop to clean the aluminum lower intake and we didn't see any problems with it.

I cleaned the block deck by hand with a razor blade and then went back over it with a small wire brush and brake clean. knowing the engine had a problem I was careful to look for a crack. WE checked inside the cylinders as best we could with the engine still in the car and did not see signs of a crack anywhere.

The old head gaskets had no sign of a leak. The man at the machine shop also looked at the gaskets and said he did not see a leak.

We drove the car around town and on the freeway a total of around 56 to 50 miles the day after we got it all back together. When we got back we added about a quart of water. (we are still running water while flushing the coolant system).

My son took the car on a 160 mile trip last night and said the low coolant light came on once. He stopped and said the coolant level was fine.

Today we started the engine and let it run up to temperature and checked the coolant level and it was still full. What we are noticing is that the residue from the stop leak the PO put in the engine is starting to coat the inside of the new radiator!

Before we tore the engine down last time we did a compression and leak-down test. Only 1 cylinder was a little lower then the others (#1) and we never heard any air coming out the thermostat hole or water pump connection.
We are going to repeat the combustion leak test while disconnecting one fuel injector at a time till we identify which cylinder is causing the problem.


Any other ideas about where to go from here?
Could the cylinder head be cracked even though the machine shop pressure tested it?

130K on the engine...

Thanks
Charrie
 

·
Registered
Joined
·
930 Posts
From what your post mentioned for info all sounds good......HOWEVER, you mentioned there was some build up of residue in the radiator. I WOULD HIGHLY RECOMEND cleaning that radiator core and use a good/best cooling system cleanser you can find. If the radiator core/tubes get restricted or COATED with the material you described, that will diminish it's ability to cool properly. And this could cause some of the HC you are seeing(scorched coolant) from over heating will show HC If you were to sample the air in the coolant resivour.

On another note, some years ago we used to be able to get a potent cooling system cleansing additive. This can be a bit difficult to find now days due to EPA regulations. If I were you I would search high and low to find some OLD SCHOOL cleaner. Once you find a good cleaner, pull the thermostat and refill the cooling system with water and some POTENT CLEANER TO GET RID OF THAT COATING. When the cooling tubes in the rad core get coated, they will loose a lot of ability to shed HEAT. Now days it's very hard to find a good potent cleaner. Guess I would talk to some radiator shops near you and see what they have that will do a good job cleaning ALL THE GUNK OUT OF THE RADIATOR AND THE ENGINE COOLANT PASSAGES.

Best of luck, Jake

PS, if there's a lot of residue in the cooling system, you might also consider knocking out a few SOFT PLUGS in the block so a more complete cleaning of the internal cooling system passages after using a strong CLEANER(ask radiator shops what works best for this).
 

·
Registered
Joined
·
6 Posts
Did you get anywhere with this yet?

It almost sounds to me like your coolant level sensor is acting up. This is a fairly easy and cheap fix, or you can just ignore the low coolant light if you are keeping an eye on the level and confirmed it is fine.
 

·
Registered
Joined
·
21 Posts
Where is the coolant level sensor? Maybe there is an air bubble by it from time to time. I know when i did my timing chain cover gasket it seemed real hard to get all the air out of the system even using the bleeder screw. My two cents. Also i noticed the amount of anti freeze in my radiator when i was draining it seemed way low, thinking my radiator was clogged up. I am going to change my radiator when i fix my ac system as i do the compressor and condenser change.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #5
Thanks for all the advice and I am sorry for not replying back sooner. I just found this thread again and thought I should update you guys. We haven't done anything else to the car other then regular maintenance since I posted last except one last flush and fill with coolant. My son siad the car is running fine and has not had to add any coolant.

The coolant level sensor was coated with the gunk that was poured in by the PO. WE installed a new radiator but used the old CLS

Mr Goodwrench , Darn,,, while we had the engine apart would have been a perfect time to remove some of the plugs and flush the block with the engine in the car!

Again Thanks
Charrie
 

·
Registered
Joined
·
54 Posts
If you want to flush the engine out I suggest disconnecting the rad altogether and mix a 1:5 ratio of CLR and water, drain the coolant and thermostat and recirculate the mix through the engine for 20 minutes then make sure to circulate water after to flush the CLR mix out.
CLR will clean that block right out.
 
1 - 6 of 6 Posts
Top