massive coolant leak

rjustman

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Nov 29, 2012
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i have a massive coolant leak at the rear of my motor.. truck is a 2002 gmc sierra. truck does not have to be running for coolant to run out on the ground. pulled fender wells and down pipe and as far as i can see it looks to be coming from top of adapter plate near the turbo drain. i looked at the coolant lines to and from the turbo with no leaks.. it does not look to be coming from the heads either. its not coming from the plate at the 2 oclock position of the adapter plate.. if the seals inside the adapter plate are bad would this happen?? seems there are weep holes on the bottom side of those seals but i cant see anything coming from those weap holes on either side.. its mostly draining on the drivers side of the motor. are there any freeze plugs on the back of the motor? also ive seen pics of the motor valley is there a plug that goes in there? i havent pulled truck down far enough to see in the valley yet..im stumped.. i bought the truck in this condition thinking it was something stupid, after reading everything on here that i could about these problems i just assumed it was a common thing that i could fix.. but now that ive spent a few hours looking at things im hoping i didnt just buy a paper weight or something thats gonna cost me my first born to repair..

please if yall could help id appreciate it.
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No.not heater core either ..it's coming from right there by the turbo oil drain that hooks to adapter plate somewhere..I bought a coolant pressure tester and didn't need it lol..it just runs out
 
Sounds like the coolant lines at the charger I think. I'm not looking at one tho


Ryan
 
One goes in the passenger side with a banjo bolt and comes out of the top to return at top of radiator right?? I didn't see a leak there..I'll look more tomorrow though..keep the ideas coming I'm listening and I'll look at everythi g you guys point out..I hope to hell it's not the seals in the adapter.
 
I'll post a video tomorrow of leak..it'll empty coolant system in about 5 minutes
 
well quick update. I got all the adapter plate off and stuff and holy SH!T.. we found what look to be pebbles in the oil cooler, the adapter plate was shot, had to order one from a member on here. the flex plate bolts would have liked to never come off.. took a 36" 3/4 drive breaker bar and had to pretty much straight arm and squat off driver front tire to get em broke loose..

following are the pictures I took of adapter plate, second one you can see a hole at the top of the coolant passage.

I have a few questions now:

we took the entire oil cooler housing off, oil filter housing and all.. was that necessary? or can I re install it and keep the coolant elbow attached to the adapter plate when I re install??
second I was told by another member that the dowel pins on the adapter plate on back side and bottom did NOT need to be re installed and that it wouldn't affect anything.. any truth to that?

also I broke the stupid NSBU assembly trying to get the plugs out. those things are glued in im pretty sure, they had a yellow dried up substance on them at the ends of the plugs and it didn't matter how soft I was I ended up breaking the switch assembly, it was extremely brittle. any words of advice on re installing that?? seems pretty easy from the write ups ive read, but are there any tricks or anything NOT to do so my truck with start and function properly after install??

this project has taken about 8 hours so far for disassembly. but that is doing it without a lift and having absolutely no idea what needed to come off and what didn't. we removed the turbo and all.. so it wasn't to bad of an ordeal.. and I think going back together is going to be a lot easier.

thanks in advance for any and all relpies.. I plan on taking more pictures and writing what I did to hopefully help the next guy who has to do this job

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Hate to ask the dumb question but why?? The bolts should hold it in its proper place right?
 
Matty is right you need them.

8 hours is pretty quick laying on your back, pulling trans, upper pan, rear cover!

Flex plate bolts should be replaced. Torque to 58' lbs, then 60* and another 60*. They are tight S.O.B.'s I normally end up with my 3/4" impact to get them off.

The oil cooler can stay on the block. The 90* plate that connects the rear plate to the oil cooler is what you have to take off and put back on. Pull the studs out and you can get it back in there. Since you already have it off no reason to go threw that though.

The safety switch.... Yeah for some reason they glue those older ones in. To put the new one in heat up the connector with a heat gun and move quick. Take a small file and knock the burrs off of the shift shaft before you install the new switch.
 
Dowels are there for a reason, mainly to properly locate an item to passages and sometimes (like a bellhousing or Cummins gear case) they actually maintain the true alignment when you torque stuff down.
Some even provide a safety margin, should things work loose.

Don't leave them out, regardless of what you may have been led to believe.

Mark.
 
I went ahead and ordered new plugs from merchant..I also opted for a,set of Arp faceplate bolts instead of the factory ones..
Yeah it hasn't been the funnest project but should be a good truck when complete.....I hope...she'll fill the spot till my fummins is done..
I Reinstalled turbo hoping I didn't have to use dowel pins like other guy told me thinking I could just slide the adapter up under that drain and then bolt down..I'm guessing if I need dowels I better take it back off, yeah? so I don't risk smearing the rtv off of the mating surfaces.
 
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Yeah he does, he posted a picture. You can't see it, tapatalk?

Running too much water, not enough dexcool.
 
No didn't need to remove,the upper only the lower..yeah I ordered a adapter from,another member..got all other parts from merchant to complete..the only thing I don't have and,refuse to spend the kind of money they are asking for them is the rear main seal tool
 
Where are you located in Arizona?

Now I understand why you were told you can leave the dowls out. The upper needs to come off to do it right. I doubt you'll be able to slide the rear housing in with dowls, with the upper pan still on. Give it a couple dry runs to see if it's do'able though. You can pull the studs for the turbo drain off the top of the rear housing. Also the down pipe shield and left up pipe shield. That may give you enough room.
 
To get upper off I was told differential needs to come out..everyone on dmax forum said it was uneccessary.yeah I figure I could take out oil reurn studs..even then though there are 4 dowels two on back side and two on bottom it would need to slide regardless..of top oil pan came out it would have to be installed before rear plate too wouldn't it?? Guess I don't see why top oil pan needs to come off.bottom one only needed to do.e off to get to 3 Allen head bolts..

I generally live in Buckeye,sundance to be exact..right now I'm up north in Holbrook for work..you know beat68cst right..your buddies with him.
 
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