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Coolant leak from Timing Chain Cover??

W

wb22rules

New member
I have a 2006 that has just rolled over 250,000 miles, the water pump was replaced by me at 225,000.

Long story short, car starts to get hot, is leaking coolant, too fast to limp it home, I meet the wrecker with new hoses for the radiator, upper and lower (originals with 250K were on it), after replacement I still have a leak.

The car has a coolant leak from underneath the water pump.
I thought after seeing this leak that the water pump must mount on a manifold that bolted to the timing chain cover, and it needed a new gasket.
I jump into my alldata account to investigate the repair and I see that the water pump mounts to the timing chain cover and there is no gasket where the coolant spews from under pressure. It is coming out from what must be a stress fracture or crack on the middle of the timing chain cover right under where the right side of the water pump is. I removed the pump and got my mirror and a bright light and I can see the red area where it is coming from.


Anybody else seen a timing chain cover do this?


I will put up pics after I finish getting it off the car tomorrow.

I found a replacement at JC Whitney for 119.00, any other places I could check for a replacement timing chain cover besides the expensive dealer part?

I will put a new chain on it while I am in there obviously, anything else I should pay attention to while I have that open?

Thanks in advance
 


did you use thread sealant on the 4 long water pump bolts? if not they could be leaking. the w/p uses a dry gasket. if you left any of the old gasket on the pump or timing cover that would let it leak. then theres the coolant elbows, they like to leak. they crack or blow apart and leak coolant real fast.

id be checking things out before buying a timing cover.
 
I did not use the sealant on the bolts, but did use a new gasket and had prepared the area. That was over a year ago. Where the coolant is leaking is not at the waterpump gasket seal, it is coming out below that about an inch and a half back of and below the right edge of the waterpump. I thought there must be a gasket there but that is in the middle of the timing chain cover.
I do not see any elbows on that side of the motor, just a coolant hose connecting to the inlet to the pump on the cover.

Where are the coolant elbows I see mentioned, the hose on that side of the motor seems to go directly to the cover, it does not appear a replaceable elbow.

I did not do anything with it today, will probably jump back on it tomorrow evening with a thorough cleaning of the area and another inspection first. worst case I can put the pump and hose back on and pressurize the system and recreate the scenario.
 
I could see it happen if say the bolt was overtorqued. The torque should be 13ft lbs. If it was grossly over tightened, the aluminum could crack with expansion/contraction.
 


Here is a picture I found of the cover I have and I circled in green where the leak is. On the car it seemed to be in the middle of the cover as I have only taken off the hose and the pump, but it appears it is a failure of the gasket between the cover and the block where the water passage is.

timingchaincoverleak.jpg

Seeing what this cover looks like by itself tells me I am going have to remove it, clean it up and replace the gasket.
While I am in there I may replace the chain and gears unless they look good. 250K I doubt it but maybe LOL. I don't have any extra money and I can hear the valve train ticking of late which leads me to believe I probably should plan on valve lifters soon, so If I think I can get another 50 K out of the chain I might let it ride and save my money for valve lifters. I am guessing they are hydraulic since I have never had to adjust the valves in the 5 years I have driven the car. The background on this car is it was a company car I got in 2008 with 65K on it, I drove it for work until 220K when they retired it and I bought it in 2011, I let my son drive it since. It burns about 1qt of oil over a 5K change and I have been putting synthetic in it since 200K, so I think it has some life left and I would like to aim for 300K out of this motor.
 
that bolt hole is one of the 4 long bolts for the water pump, those need sealant on the threads or they can leak. id think thats what happened here.

id try to take the 4 bolts out, clean them up good, then apply some thread sealant. and put them back in, see if the leak stops.

plumbers thread sealant works well. they sell it at the parts store.
 
I will certainly try that first and see if that stops it, but since that gasket area has already been breeched I am not hopeful.
Worst case I just put together the total repair parts wise at autozone and its not that bad, even if I go all out and tidy up a few items that literally owe me nothing at 250K.


Oil Pan Gasket 11.99 D1800

Timing Cover Gasket set 58.99 TCS46077 includes timing cover gasket, water pump gasket, oil pump gasket, crank seal and an o ring

optional

Crank Position sensor 39.99 if you care while in the area SU198

Cam Position Sensor 33.99 same reason SU196


Timing set 69.99 includes chain, both gears, dampener and tensioner


totals out to 214.95 if you want to make sure you don't have go into that side of the engine again for a while ;)
 
Could be either in that area IMO. There's a coolant port and a bolt that goes into the coolant jacket.

On the parts. I'd replace the timing cover gasket only. Quick easy.. RTV the pan gasket right there and presto.. all fixed up. At 250K do you really want to fight that stupid U bracket that you guys have as a motor mount?
 


060228GM00-344.JPG
 
Sorry for the delay, had a PC down for couple days and another vehicle issue keep me busy.
1 Failed computer power supply and one rebuilt motorcraft alternator later I was able to do some work on it last weekend.

Sealant on the bolts was no difference.
Picked up the parts above as well as the elbows.
I was able to see the elbows once I could look at it when the sun was out.
That's a nice illustration Thompsju
Hope to get back on it this weekend, I have most of the items out of way, just the harmonic balancer and the cover bolts left to get it off.
I like the idea of just RTVing the oil pan seal, as dropping that out and replacing the gasket looks to be a pain in the arse.
I will just return that gasket.

I will check back in after I dig back into in it Saturday.

I may remember to get Pics
 


I've done many cover pulls and each time used RTV on the cover. GM has that in the FSM as part of the timing cover replacement procedure.
 
Sorry for the major delay, but today I was able to test drive the repair and nothing leaked :) .

I think if I had put silicone on those long bolts when I replaced the water pump last year I would not have had to do this. But the replacement procedure I was following did not reference any silicone. I think what happened was the bolt got compromised for lack of silicone, than the blowout from the bolt compromised the gasket beside where the bolt passed. It did not appear funny looking when I removed it, but after applying silicone to the bolts I still had a major river pouring out of the area circled where the gasket got compromised between the coolant passage.

I had a few delays during this repair, as is obvious by the date of this response, that cost me time. I do not have a regular shop, just an attached garage to the house and the basics as far as tools. Luckily I have two more vehicles than I need so I can let a repair take a while without putting someone out of a vehicle.
The first delay was not having a good way to hold the flywheel like the service procedures show with that special tool, I used some steel I had to make a tool to hold the harmonic balancer. The 1/2 inch drive socket extension I had borrowed was flexing so bad trying to remove that harmonic balancer bolt I went down to harbor freight and got a 3/4 inch drive set so as not to risk breaking my neighbors long 1/2 inch extension. That and the tool I made got the harmonic balancer off. That was three weekends of time as one of those was good warm weather and I played golf rather than work on the car ;)
I got the timing cover off and the next step that hung me up a bit was trying to drop the oil pan as the service procedure described. First off there is a bracket that bolts to the engine and transmission that blocks access to one of the oil pan bolts. Getting this bracket loosened enough to loosen the oil pan bolt underneath it was a major pain in the arse. I had to borrow an air compressor and a air ratchet in order to get two of the five bolts holding this bracket loose. I did get the bracket bolts out, but the bracket still could not be removed, just moved just enough to barely get the last oil pan bolt loosened. I loosened all the oil pan bolts intending to drop it a bit as the service procedure stated. In order to drop the pan the engine must be supported from above as the motor mounts are under the oil pan on each side, that I did not accomplish. I ended up saying screw that as I did not want to waste another day trying to fabricate a motor support tool in order to raise/hold the motor. I just RTVed the bottom of the cover and replaced it with the new gasket against the block.
I did change the timing chain and sprockets as they were fairly cheap, but when I pulled the old ones out there was no discernible wear even after 251,000 miles.

I do think I need to find a scan tool that will allow me to initiate the relearn procedure for replacing the crankshaft position sensor, but the car runs great and exhibits no issues or engine lights after a couple short test drives. My auto tap tool does not let me initiate a relearn procedure. Is there a way I can get the computer to do the relearn procedure by doing a certain driving scenario, or will I need to get access to a scan tool to initiate the relearn for changing the crankshaft position sensor?

I appreciate the help on this from the forum, I am sorry I did not post more during the repair but RL and computer issues had me down for most of the time, thanks in advance for any help again.
 
A week of the boy driving the car and all is still dry, no oil drips from where I used the RTV against the oil pan and no coolant escaping from the new gasket on the cover. :woot: I had a check engine light come on last weekend as I used the car for a short hop twice in a row, but it was for the coolant temperature being below thermostat value on a 4 degree day, I have had that before on really cold days and I think the thermostat is working correctly, it was replaced 2 years ago for the same code while it was a company car, I cleared it and it has not returned. I still have not arranged to get my car to anywhere with the tool to initiate the relearn procedure, but it seems to be running fine so far despite not doing that. I do have two different friends that can probably hook me on that, so I will hopefully get the car over to one of those shops they have hookups at and get the relearn done for changing the crankshaft position sensor in case it costs me a bit of MPG or something by not having that done.
 
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