Thread: How does coolant leak from the timing chain cover??

Hey, all, this is my first post here, and I'm a bit confused. I'm trying to figure out where my adult daughter's leak is coming from in her 3.8. She called me up one morning and said her car was showing hot, (but not topping out in the red), and the heater hadn't been working right, either. I had her bring it over and I pulled the heater hoses and applied air pressure to back flush the Dexcool crud out of it (fixed the heating problem), then changed the thermostat, added about 3 quarts of water, and it seemed to fix the temp gauge issue. I told her to bring it back a couple of days later so I could flush the radiator and engine.

Well, since this was my first go round with a grand prix, I wasn't aware of them not having radiator drain plug, and after a frustrating attempt at getting to the lower hose clamp, then finding out the tool to allow me to get it off there was $70 at NAPA, I just had her take it to a local mechanic to flush on her next day off. We scheduled her with a reputable local shop, and they did the vacuum/flush route.

A day or two later there was a puddle of antifreeze under her car, about 8" in diameter. I had her bring it back over on her next day off so I could find the leak. When I couldn't locate the leak, I took it back to the shop that flushed it and asked them to check it. I also asked how much pressure they used to back flush it. The guy checked out the engine running, and showed me with a mirror where he thought it was leaking, which was at the lower right hand side of the timing chain housing, right behind a bolt, and told me he thought the timing chain cover gasket was leaking, and it was a common problem with "these engines". I was thinking he might have put too much pressure to it when flushing it and blew a gasket, but he assured me it was just enough to force the water out.

Anyway, I'm the kind of guy who works on my own vehicles, but sideways engines are a pet peeve of mine. But what I don't understand is, why would a coolant leak be coming from the timing chain housing?? There's no coolant in a timing chain. Also, I should mention, the upper plastic elbow isn't leaking, and if the lower is, I can't even find that part. The closest I came to that was unhooking the heater hoses to flush it, but there was nothing leaking there. Is there something that might be leaking at the water pump that I'm not seeing? Is this "the timing chain cover gasket is the culprit, and you may as well get a new water pump while you're at it" call a common problem or a common scam? Oh, yeah, he quoted me $400-450 for the cover gasket replacement job, and I'd have to pay for a water pump if I went ahead a replaced that, too.

This all rubs me the wrong way due to an instance I had some year back where I had the heads replaced on an '82 350 Blazer by a local Chevy dealer shop, and when they were done, the told me the head was cracked and leaking coolant. The kid showed me the leak, which I was unsure of it's source, but I had them pull it so I could take it back to the guy who rebuilt the heads and mag tested it. No cracks whatsoever. I took it to another shop, which correctly told me when the dealer put the water pump back on, the gasket didn't seal and it was the water pump leaking, not the head gasket. I've lost all faith in not only shops telling me the truth, but worse than that, incorrect evaluations.

So, I'm here to ask all of you experts on these cars, why would a timing chain be leaking coolant and not oil? I'm a retired Ironworker, but I don't like forking over money to fix something that wasn't the problem. Thanks in advance for any comments or advice. Butch Butcher

My radiator drain plug= pulling the lower hose off and let it drain. Screw messing with the rad. petcock. They make aluminum replacement elbows. They are in the "Help" section at most auto parts stores. Comes with both elbows.

What year is this GP? And where in MO are you located?

thanks for the replies, fellas! Scottydoggs- I've watched a few youtube videos trying to find info on locating the radiator drain plug (Britt's gp is a 2008, which I've found do not have plugs or petcocks) and found other helpful vids on those elbows and the suggestion to replace them with metal/aluminum parts, and also on back flushing the heater core to find the quickest, easiest steps and to not ruin something unawares. Also saw one where a guy actually did show a leak from behind a bolt in a similar spot as ours. I just still don't understand how a timing chain cover could leak coolant instead of oil, though. But thanks for the tips and I will try your method of 'drying then checking'.

tzerilli- Hers is an '08 and there are no drains of any type under all that plastic. I removed the front lower clip to get to it, and used a mirror, then stuck my head up there. I found on a forum somewhere (else) that another '08 owner confirmed this. The 'leak' the mechanic showed me via a light and mirror was at the bottom of the timing cover, but that means it could be coming from anywhere above, the way I see it. He pointed out a pink glob, which he said was sealant from a previous change, but it may have been a gasket popping out, I don't know. From what I've read, these use metal, rubber or silicone coated gaskets, so a chunk of gasket being pushed out doesn't sound right to me. Your description of getting into that hose is about right. I tried channel locks (no room for the handles with the cooling lines and fans in the way), then some vice grips (still too tight), then finally a small pair of needle nose vice grips, which I still couldn't get in and locked. The neat tool I found at NAPA looked like something from an OB-gyn's office, but at $70 for a one time use, and the pain of removing that plastic again, I chose to send it to the shop, which ended up costing $115. Should have bought the tool, but my daughter has told me she will be getting rid of this car asap, so I may never need that tool again.

Fordman77- Yep, pulling the hose use to be an easy job. Although my daily driver is a '51 Chevy pickup (original, except for a 235 in place of the original 216), and even it has a petcock on the rad, although the hose is right there and easy to get to. Even my '04 Siverado 3500 with it's Duramax diesel has a drain. I just can't believe the shirt and tie cubicle guys who came up with the horrible idea of cheaping out on a bottom drain on these cars actually thought it was a good idea to eliminate that. Absolute proof that the designers have never gotten under one to do the job themselves, IMHO. Per where I'm at in Missouri, I'm not too far from you! We've lived in Park Hills, between Bonne Terre and Farmington, for 25 years, but I bought 43 acres outside of Fredericktown that we're building on this summer. An injury 10 years ago on a job knocked me out of the Ironworkers (local 396, St. Louis) when a 35# block fell on my head and messed up my neck/back/shoulder and gave me permanent head aches, but when the settlements and lawyers were all done, we were able to buy some land so we can get out in the country and out of town. I'll probably be heading up to STL today to stop by the hall down off of Hampton on Elizabeth Street. After working up there nearly every job for 30 years, I'm usually up to the city once a week or so.

Thanks, guys, I'll probably get out there and, as much as I hate the idea, tear into the machine and change those elbows and the water pump, then. I hate to get too deep into any engine (timing cover, for instance) for fear that i'll cause more damage than repair, but my 33 year old daughter, who has 3 elementary school aged kids, is going through divorce with her husband right now, so we're trying to help her all we can. And on pension, soc sec and a second injury fund payment, sometimes 'helping' can put a strain on the finances, so Papa get the call and the tools get drug out to the curb. When I was younger, I was naïve enough to believe that when your kids grow up and move out, they magically fend for themselves and don't need as much funding as when they were young. not. But they're still your kids, and you still want to help, no matter how old. Thanks again, guys. Butch

Timing covers do leak coolant. Had to change my 2007 gasket 3-4 hour of taking stuff off and putting it back together. Scotty walked me through it and was fairly easy. There is a thread on it somewhere. Search timing cover gasket.

I think vacuum extraction is becoming the norm. All my newer vehicles have no radiator drain plug.


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showme, everything youre looking at doing isnt that bad. i believe theres a write up in the "how to" section on both the elbows and the water pump-make sure to put a sealent on those water pump bolts when re installing.
i did a blackflush on the heater core of mine along with all hoses,pump, tensioner,elbows, rad flush, tstat, and all that good stuff. i didnt work at repair shop speed-my mind says i can but my body laughs and says,"sure-go for it. ill be crying in a bit." got it all done in about 5-6 hours.
i have an 08 and theres a PITA to get at petcock on the rad. weird!
id take your daily driver any day!

ok, folks, I'm under the hood today, and I've got the old pump out and getting ready to install the new one. I have a question that I'm a little (lot) confused about, and that's the thread sealant on the long bolts. I've seen Loctite mentioned, and I have both blue and red threadlocker, but is that what they're talking about? Or something different that Loctite makes. The bolts I took out have a white looking stuff on them, so I'm now wondering if by thread sealer it means something like Teflon tape for plumbing?? Or will threadlock seal ok? I saw in one post that a guy asked the same question and scottydogs replied that it needs to show certain letters (pt??). I sure the hell don't want to put this back on and have to take it off again! if anybody is listening right now, please let me know asap. I gotta get my daughter's car back to her by the time school is out in 3 hours. Thanks! Lee

Got the sealant, came home and quickly sheared a small bolt trying to torque it to 12ft/lbs (#%!~*!!!). 16ft/lbs my ass! The larger ones did fine with 25#'s, but I could tell early that 16 seemed too much for the little 3/8". Now for the fun of getting a bolt out with 1/16" of thread sticking out. At least it's on top. First, I have to find another bolt that matches, then either drag the wire feed welder out and attempt to tack a nut on, or go through the fun of drilling and extracting it without really messing something up. It's times like these that I swear i'll never turn another wrench again. And it's going to rain.

if the broken bolt doesnt have enough to get a nut on it, ya might be able to take a bolt the same diameter or a little smaller, chamfer the end, and tack it on top of the broken one.
look at the bright side- you have a mig welder to try before the drill and easy out!
dont know why they named those things easy out. dont think ive ever had a predicament where it was easy. shoulda named em
simple out

i didnt use a torgue wrench when i had the front of the engine apart or even on the trans pan. no leaks or problems so far after about 8,000 miles.

Thanks again, guys. I appreciate the inspiration and information. Here's the update. I welded the nut on the bolt and it backed right out. Had to cut up an old set of leathers and poke a hole in it to keep from scarring the mounting face, but it was an old burnt up jacket anyway, so that's good. I went down to Fastenal and they had the bolt (pack of 10, of course. Fastenal doesn't believe in selling you just what you need. ever. But I got some grade 8 5/16". Due to the permanent washer on the old bolt, the new one's were a little long, so I added a washer and a lock washer to get it to right. But THEN! I couldn't find one of the long bolts, so had to make another 8 mile drive to Fastenal at 4:55 to get another bag o' bolts. I waste more time fetching than I do wrenching. Then I found the lost bolt under a shop towel, which is good. Forgot to mention, I went to NAPA and got some Permatex thread sealer. Thanks, scottydogs. I'd rather have Loctite, but this'll do. The pump is on, and that's a relief. So next I went for the elbow replacement. All is going well, until a few minutes ago, when I found that the OEM elbows Rock Auto sent me seem to not match what came out of this car. I've been under the impression that both these elbows were the same, which is what I got from RockAuto's match for this year and model. But the forward elbow that came out of the engine has a longer arm leading into the block, so they're two different sized elbows(??). The new elbows won't reach into the block at the front elbow connection@ And the tensioner housing won't go any closer. It's just one damned thing after another on this thang! So, here I am, looking at two old elbows (all ends broke off except for one on the rear elbow) and hoping an Auto Zone or O'riellys has on that will fit, since NAPA is asleep for the night. That said, it does look like there's some sludge that's been running out of the forward elbow at the block. Ok, it's getting late and my tools are on the sidewalk, so I'm off of here. Any suggestions or comments are very welcome. I'll get back on here after a quick drive to the chain franchises.

Now, for my latest dilemma,

Went to AZ and they had some that fit, but not metal. I was just happy to have the right ones. They're in and everything went back together fine. I do have a spare flange nut, like the three holding the alt on, but I can't remember where it came from. Probably something critical with my luck. Speaking of that, after I got it all back in place, I added 3/4 gal. of coolant to top it off before I started it up, and I heard a drip. Checked the original timing bolt the shop guessed at, and it was dry. But the bottom center bolt on the pump was steadily coming out at the gasket. I must have hit the bottom first when I placed the pump and moved the gasket. It had gotten a little wet when after taking the pump back off when I sheared that bolt. Should have changed the gasket, but it stayed in place and didn't look bad. Just wet below the rear port. Anyway, tomorrow is another day. And the third time is a charm. I hope.

Well, it seems all is well and done. I pulled the pump back off yesterday and it was the gasket, which had gotten wet enough to let it sag, and when I removed the pump, the gasket was torn and it was indeed pulled down a bit. At least the replacement is metal/silicone and is doing well. I had a scare after I took it for a ride and rechecked the pump and found the lower front long bolt was backed out about 3/16", even though I torqued all the 5/16 bolts to spec. It wasn't leaking, thankfully, but I couldn't figure out how it worked its way out. The sealer did it's job, obviously, but it just happened to be the one bolt hole that seems to be clogged with dexcool mud (the other 3 weren't). The threads were crudded up with the red stuff every time I pulled that particular bolt back out. I figure the bolt not being all the way home was due to some crud, or something, because my torque wrench absolutely clicked at 25ft/lbs. But I will never walk away after torqueing without taking a second look at the bolt I just heard click again! It seems to be holding fine after an hour of driving in search of a Loctite stripped thread repair (form a thread) kit, just in case. Anyway, I also cranked the suspected timing cover bolt and it seems to be dry so far, also. So thanks, everyone, for the guidance and help with this project. My daughter plans to sell this car sometime after their divorce is finalized, so I may not be around for long, but I'm sure glad I found you guys. So far, I've replaced her tires, throttle body unit, the thermostat, flushed the engine and replaced the dexcool with green, backflushed the heater core, changed out a rear window regulator, re-glued the rear headliner, and changed the oil. But this morning, I'm sure I heard the front discs rubbing, so I guess I'll be doing the brakes next weekend?? And so goes life in southeast Missouri. I am much obliged to you all. Lee Butcher