coolant crossover pipe leak? - now with photos

[npfd]

Hi there,

 

I did a search on this forum, google search, and posted a few things about coolant leaks.

 

Unfortunately we're on our second pump, and there is still a coolant leak.

Looks like it was puddling up on a shelf where the lower motor mount is. After cleaning it out several times with water, coolant is still accumulating there.

 

The area where the AC compressor sits is wet. The valley from the Intake Manifold, is moist and gunked up. I poured water from this area, thinking that it could be from the metal crossover coolant pipe, and it flows exactly as if it leaked from there. But its not fresh from there, only gunked up and moist.

 

Today I tried cleaning it and will see. Can the coolant crossover be rusted and leaking from the top to bottom without evaporating? The piece that goes to the Intake Manifold is press fitted?

 

The water pump seems fine this time, as it not wet right underneath it.

 

Could it be the front, black, coolant bypass? We're gonna have another look tomorrow.

The coolant loss seems to go down about an inch every ~2-3 weeks.. It starts off puddling on the shelf, then leaking into the mount, then spilling onto the driveway.

 

CS with 3100 V6, around 218k kms.

Edited June 16, 2011 by npfd

[AL]

Sounds like the lower intake gaskets are leaking

[npfd]

hmm that's uncool, because we personally changed it in 2006.

The rear of the block is moist too, like pulley area, below PS.. and firewall side...

[AL]

Can you get a pic of where you notice the leak starting

[DaveB]

I am guessing either LIM or head gasket. I have a post where mine was leaking in the same place near cylinder 2. It looked like the water pump that I replaced twice. I had also just done the head gasket and LIM (doh!). I installed (kind of a pain but ended up being worth it) a prestone flush kit ($15). Basically you just hook a plastic T with a screw on cap inline with one of your heater hoses (has to be the right one, can't remember at the moment). You put on a one way attachment that comes with the kit on that T that prevents leaking. Hook your hose to it. You simply turn on the hose, get a good flashlight and a bendable mirror ($7 at Harbor Freight) and watch where the water comes out. On mine it was the head gasket again! I re-used the upper and lower gaskets and put in a new head gasket and it is now dry as a bone.

[npfd]

Thanks for the input, now I'm starting to get worried... I haven't noticed any mily substance underneath the oil cap, only condensation in winter for short runs.

This flush kit sounds cool.

 

Alright so I took some photos....

 

We cleaned and picked the coolant bypass, there is rust spots, even at the weld joint near the bleeder valve but looks okay. It gets gunked up below the front passenger engine mount.

 

There are always spots of coolant on this guard after a run, it dries up after a while. And looks like the coolant from here goes on a shelf where the lower motor mount is

 

lower than the belt tensioner, where the shelf from the dirt guard is, I see coolant accumulated in the back of it.

 

 

Here where the lower mount is, and where coolant is leaking from, you can see the drips onto the driveway too.

 

 

I stuffed the rag where to find out over the next few days whether its from here. A sidenote is that its all gunked up behind the PS pump, even from the LIM. I cleaned it up a bit. Another note is that I poured water from this point, and it falls to right behind the water pump, where its wet after several days, and pools up on the mount shelf. Also the pulleys below the alternator, are freshly wet also, this was noticed from another time we jacked the car up, removed the front dirt guard and ran the engine for 10-15 mins and couldn't find the source of the leak.

 

 

This is the area behind the pump thats wet, like the block and all. And which pools onto the mount shelf, then leaks through the mount.

As mentioned the LIM was changed in 2006 to GM parts, we tightened the bolts to specs, and I even tried two that can be accessed without removing anything and those seemed good.

In addition today, we cleaned out the coolant bypass, I looked with the mirror underneath the plenum, with a flexible mirror, and see that there is corrosion on the top part of the metal coolant crossover pipe. Not as bad as the part entering, can be seen in the first photo.

 

From what we've checked out, it looks like its coming from the top part, and pooling its way down, judging on what's wet... could it be leaking from the top part, I'm guessing crossover, or something else, then evaporates on the LIM, but appeas below the Alternator, and water pump?

 

I'm fed up of this haha. It its something major I hope not... then we're gonna leave it... unfortunately!

 

Thanks again!

[John G.]

Had same problem on 1996 Lumina 3.1L. with 210K miles. Did the LIM gaskets - had engine oil in coolant reservoir and had to keep adding coolant. Corrected the oil in coolant problem. Still had to add coolant every month. Occasionally noticed coolant on front engine mount. Finally after about four years of playing hide n seek shined a light on a freezing night on a hot engine and noticed a fine jet of coolant spraying out on the left side (fire wall side of engine) of the timing chain cover (below the power steering pump). Later also noticed coolant seepage on the right side of the timing chain cover (radiator facing side of engine). I just got done replacing the timing case cover gasket. ( A real knuckle buster). The old gasket was like jello around the coolant ports. I believe DexCool was responsible for that. I finally gave in and went to a high mileage universal green-yellow coolant. But also check for a leaking water pump seal. With the engine off, run your finger on the bottom of the water pump pulley to see if there is a drop of coolant hanging there. Do this with engine cold and after a drive when hot. If dry then the timing chain cover gasket is your problem.

Edited June 17, 2011 by John G.
spelling

[DaveB]

@npfd - Looks like you got the engine cleaned up. That helps to find a leak. My leak also ended up in the exact same spot as your 4th picture. Cylinder 1 (rear head near power steering pump) and 2 (front head, same side) are the most common areas of weakness from what I have seen and heard. My LIM was replaced 2 years ago (oil in coolant) and then I had the head gasket problem. I personally believe your problem is probably the rear head gasket at cylinder 1 or the LIM since it sounds so similar to the problems I had which were: Phantom leak, no oil in coolant, losing coolant, LIM already replaced. I am certainly no expert so take my opinion for what it is.

 

Here is what I think is a great post to get an idea of what you would be into if you did replace the head gaskets. I personally got the motivation and information from this post to do it myself. I am going to keep looking at your pics to see if I can find anything else to add.

http://hubpages.com/hub/Chevy-31-Liter-Engine-Leaking-Intake-Manifold-Gasket-and-Warped-Heads

 

@John G. - Whew, after looking at the manual replacing a timing chain cover sounds even worse than changing a head gasket, yuck. Per John G.'s response, in my case I had coolant drips hanging from my water pump also but it was not the water pump as you might expect.

Edited June 17, 2011 by DaveB
Trying to put in spaces..

[alec_b]

Sounds just like what mine's doing. It's the timing cover. The mystery leak on that side of the 3x00 engines a classic timing cover gasket gone bad.

[npfd]

Thanks a lot dudes. I did run my finger several times to check the seal at the pump, its fine. So no go on the crossover, I'm thinking it if was leaking it would do it all the time, consistently.

 

@JohnG, dexcool from inside the motor caused this?

 

@DaveB, would the headgasket going at cyl 1, cause coolant to seep behind the waterpump?

 

@Alec_B, thanks man... I never new this was a classic thing on these motors, I thought it was only the LIM. How about the new GMs, like the Impalas with the 3.5?

 

 

I looked up the online manual, http://arrc.epnet.com/autoapp/8800/8800.htm and its a big job. I don't know if we'll be up to doing it. Because some other things on the car isn't 100%, and we're only keeping this car up till next year, then its time to part ways.

 

Does anyone suggest any stop leaks? There is some on the Canadian tire website.

 

http://www.canadiantire.ca/AST/browse/4/Auto/3/AutoFluidsChemicals/EngineTreatments/PRD~0380844P/Rislone%252BPelletized%252BRadiator%252BStop%252BLeak.jsp?locale=en

 

http://www.permatex.com/resource_auto_archive/pr_auto_07252007.htm

 

http://www.canadiantire.ca/AST/browse/4/Auto/3/AutoFluidsChemicals/EngineTreatments/PRD~0380817P/Prestone%252BStop%252BLeak.jsp?locale=en#BVQAWidgetID

 

I heard of GM stop leak tablets? Anyone have any ideas?

 

Thanks.

Edited June 18, 2011 by npfd

[DaveB]

Per your Q, maybe, insofar as my head gasket leak on the front pretty much took the same path from the engine block.. The coolant would lie in the valley on the block and eventually make its way behind the water pump down to the ground. When the car was running it would get tossed around by the belt making diagnosis harder. I was sure it was the water pump and I replaced the gasket twice then replaced the pump and I still had the leak. Then I thought it was the timing cover (see my post earlier: http://www.w-body.com/showthread.php/51019-Who-can-do-CSI-on-my-coolant-leak). I have a few pics that I might be able to dig up for you to compare it to.

 

I think if you are only keeping it for a year, throw in some stop leak and call it a day. I personally plan on keeping mine for many years to come.

Edited June 18, 2011 by DaveB

[Andrew]

dont fall in to the 'dexcool eats gaskets' BS. It is just that. BS.

[John G.]

I've been following the DexCool saga for years and was always skeptical of the bad rap it is given. But I also seen an interesting web posting by an individual who appears to have done his homework on that topic. Including electron microscope images of different gaskets exposed to DexCool and the subsequent erosion of the bonding material. In my particular case the gray-paper gasket used in the timing case cover was like jell or grease around the coolant ports. All other area of the gasket was the usual hard brittle composition you'd expect after 14 years of baking. So that makes me a little suspicious. Since the green or yellow universal antifreeze is made for long-life (5 yrs/150K mile) service and costs less I'll give it a try.

 

Also, a tip to anybody replacing LIM gaskets. Initially I used a no-name brand gasket kit. Six months later I was redoing the job. This time using Fel-Pro. Also the four diagonal bolts on the LIM need thread locker (blue) as they loosen up after several months.

[DaveB]

That is a fantastic tip on the diagonal bolts. I found that out the hard way. Not to mention that if you torque them down just a wee bit too much you will strip the threads. I swapped the stock 20mm bolt for a 25mm replacement and I was able to to tighten it without resorting to a heli coil.

 

Couln't agree more on the Felpro quality. I always hear about them being better and now I have seen it.

[npfd]

@DaveB, thanks for the info. If you the few pics that would be great to compare! Helicoil I'm surprised you mentioned that, hehe you got all the tools? I heard felpro is really good too. I saw the quality of my neighbor's gasket, when he did on his 98 GP, metal backing...

 

@Independentfool, yea I figured Dexcool is fine, I even did a quick search after, some people had no problems...

 

Now that I think of this problem we're having. Could the headgasket be a slow leak over years? Because I do recall having to top up coolant once every while... and now its just getting a little bigger?

 

I'm stumped whether to get rislone stop leak, for radiator (cast iron block alu heads) and other gaskets thinking that it would help the headgasket, its 10$. The Rislone headgasket one is 32$ canadian, which I find a bit much. Its expensive I find.

 

So for sure not the crossover part? I did think it lost more coolant in winter. ..

 

Thanks.

[npfd]

update - so I added some all weather sealer to the coolant, and for now it does sound different, I could be wrong. I also noticed that air bubbles come from the coolant reservoir on idle.

 

I remember having a really hard time bleeding the system last time we refilled coolant, the only way it would work is going for a run. The bleeder valve didn't seem to do the trick.

 

We'll see over the next week what we're gonna do and how its acting.

[DaveB]

npfd, OK, I dug up some pics. Some of these are screen captures from video. I thought I had a couple other his res pics but these should give you the idea of what I was seeing. First one is with the water pump pulley pulled off. This when I have the hose hooked up you can see coolant running down the same part of the block as your pics with very obvious drips hanging at the bottom. In the 2nd picture you can see the coolant hanging in the same spot as yours. The next two show the before and after of the offending part of the block. You can see how bad the coolant system was and how clogged it was. The second shot of those 2 is when I replaced the head gasket the second time. The last picture is the spot in the block valley where coolant was pooling and would run down from there. You can see that area better in the previous pic. The circled area is the block where it meets the head at cylinder 2 where it would leak under pressure. Once again, while it was running I was sure it was the water pump or maybe a hole in the back of timing chain cover that houses the water pump that was throwing water in that valley and I didn't really see it leaking from the head/block.

 

Edited June 24, 2011 by DaveB

[DaveB]

update - so I added some all weather sealer to the coolant, and for now it does sound different, I could be wrong. I also noticed that air bubbles come from the coolant reservoir on idle.

 

I remember having a really hard time bleeding the system last time we refilled coolant, the only way it would work is going for a run. The bleeder valve didn't seem to do the trick.

 

We'll see over the next week what we're gonna do and how its acting.

 

The bleeding is HUGE pain and maybe this will work for you. I finally got it to work for me the last time (about the 10th time!). Forget the bleeder near the thermostat. Use the one above the water pump. Looks like the highest spot in the cooling system to me and therefore where the air would pool. With the engine off, fill the radiator as much as you can. Unscrew the bleeder and you will hear compressed air escaping. Once it stops hissing close it up and add coolant again. Just keep repeating these steps until it doesn't hiss anymore. I was able to get it filled and never had any air pockets.

 

As far as bubbles, from what I have read it could also mean a exhaust gases escaping from around your head gasket. There is a way to test if the gases are exhaust gases (some sort of guage you attach to your coolant reservoir) but I never did it. Again, sounds to me (take it as you like, I am not an expert) like you have a head gasket problem.

Edited June 24, 2011 by DaveB

[npfd]

Thanks a lot Dave. Its great to compare photos and see similar problem. Yea well I guess its gonna be game over soon... the winters here in Quebec have taken a toll on other areas of the Olds...

 

The bleeding process its good to know, and I may see to it..... ya the bubbles is another story hehe.

 

Does anyone know if the 2009-2010 Impala 3.5 has similar head gasket prbs down the road, as its the cast iron and aluminum heads... since for 2012 they are now using an all aluminum block.. depending on what may happen it may be a replacement for the Olds, but once I got enough funds in a couple of years...

[ricklaverd]

I know its old but if anyone has the same problem its the Engine Coolant Outlet Gaskets 15 and 16 in the diagram. Your 1st guess was right crossover pipe leak