UIM/LIM gasket questions (yes, I have searched and read some)
#11
DINOSAURUS BOOSTUS
Expert Gearhead
Ok, I'm busy and skipped most of the posts. I'd like to clear something up and Dan, I'm sorry I need to really drill this home for all of us.
The UIM GASKET IS NOT A COOLANT ISSUE ON THE L36 MOTORS THE PROBLEM IS THE UIM ITSELF IN 99% OF CASES.
I do not suggest typically doing the plugs with the manifold on the motor, but in teh case of new gaskets as Dan had done on that car, i told him to do it on the car. The little amount of metal in the cooling system was minimal and should be avoided if possible. Another way to block the ports is to clean and fill the coolant tubes in the UIM with something like JB Weld.
LIM gaskets: while they look horrible "most" of the time when we pull them out, they typically don't cause any idle or running issues. The path from the coolant port to intake runner would mena that the coolant would have to get through two seals and travel nearly sideways. It'* possible, but is one of those things that doesn't seem to happen. Coolant seeping straight down through one seal and into the oil is more common and yet we hardly see that happen.
To address that coolant you have seeping onto the top of the manifold. That is because there is no seal around the bolt except some sealant GM puts on the bolts themselves. When you pull the bolts for the LIM, you will see some goop on them. That'* the sealant, your issue of seeing coolant on top is because that sealant has leaked and the LIM bolts are in coolant and oil passages of the head. Coolant is under pressure in the head and the oil is not, therefore it is more common for the coolnt to pool on the LIM in the recessed areas.
Sorry if I'm coming off as a d'bag the points I stress are only to keep others from doing rework, no one likes going back into a car after a repair epescially in the cold winter months.
The UIM GASKET IS NOT A COOLANT ISSUE ON THE L36 MOTORS THE PROBLEM IS THE UIM ITSELF IN 99% OF CASES.
I do not suggest typically doing the plugs with the manifold on the motor, but in teh case of new gaskets as Dan had done on that car, i told him to do it on the car. The little amount of metal in the cooling system was minimal and should be avoided if possible. Another way to block the ports is to clean and fill the coolant tubes in the UIM with something like JB Weld.
LIM gaskets: while they look horrible "most" of the time when we pull them out, they typically don't cause any idle or running issues. The path from the coolant port to intake runner would mena that the coolant would have to get through two seals and travel nearly sideways. It'* possible, but is one of those things that doesn't seem to happen. Coolant seeping straight down through one seal and into the oil is more common and yet we hardly see that happen.
To address that coolant you have seeping onto the top of the manifold. That is because there is no seal around the bolt except some sealant GM puts on the bolts themselves. When you pull the bolts for the LIM, you will see some goop on them. That'* the sealant, your issue of seeing coolant on top is because that sealant has leaked and the LIM bolts are in coolant and oil passages of the head. Coolant is under pressure in the head and the oil is not, therefore it is more common for the coolnt to pool on the LIM in the recessed areas.
Sorry if I'm coming off as a d'bag the points I stress are only to keep others from doing rework, no one likes going back into a car after a repair epescially in the cold winter months.
#12
Retired Senior Admin
Expert Gearhead
Join Date: May 2006
Location: Sheboygan Wisconsin
Posts: 29,661
Likes: 0
Received 28 Likes
on
24 Posts
I shoudl point out, the UIM gasket I just changed was leaking to the outside, not the inside. After changing it the UIM failed 2 days later. As Bill stated, the LIM gaskets look bad, but rarely leak in to teh engine, and when they do, it'* only seeping.
#13
Member
Posts like a V-Tak
Thread Starter
Join Date: Apr 2009
Location: Virginia
Posts: 59
Likes: 0
Received 0 Likes
on
0 Posts
well, I ordered up the UIM (comes w/ "all gaskets needed") and the LIM gasket, Rockauto, shold be here Wednesday. Hoping to get to it on Friday and/or Saturday.
Bill... d'bag? lol, don't worry about it. You guys seem to have been doing this stuff for a long, long time, your advice is appreciated. I've always done my own oil changes, radiator flushing, brakes, plugs, alternators, etc., just never been into an engine before. It'* great to have a resource like this where folks give up their time and knowledge.
Danthurs, thanks again. I'll ck back in now and then to see if anymore advice pops up... hope I won't have to come in here in the middle of the job for an emergency!
I saw the torque specs for the UIM and LIM bolts somewhere, I'll hunt them down again unless someone has them handy or a quick link to them.
Bill... d'bag? lol, don't worry about it. You guys seem to have been doing this stuff for a long, long time, your advice is appreciated. I've always done my own oil changes, radiator flushing, brakes, plugs, alternators, etc., just never been into an engine before. It'* great to have a resource like this where folks give up their time and knowledge.
Danthurs, thanks again. I'll ck back in now and then to see if anymore advice pops up... hope I won't have to come in here in the middle of the job for an emergency!
I saw the torque specs for the UIM and LIM bolts somewhere, I'll hunt them down again unless someone has them handy or a quick link to them.
#14
Retired Senior Admin
Expert Gearhead
Join Date: May 2006
Location: Sheboygan Wisconsin
Posts: 29,661
Likes: 0
Received 28 Likes
on
24 Posts
LIM bolts, 132 inch pounds in sequence, check the LIM change write up for that. UIM is 89 inch pounds. Start with half torque, then full torque or you risk cracking the plastic.
Once your done your going to stand there, scratch your head and wonder, why was I so stressed. That was easy.
Once your done your going to stand there, scratch your head and wonder, why was I so stressed. That was easy.
#15
DINOSAURUS BOOSTUS
Expert Gearhead
On the plastic upper, when torqueing it ..I tend to start at half and then go up by 10 inch lbs in steps. Watch each of the ears as you are torqueing them down. Any signs of white or cracking, that bolt is torqued all that you're going to do successfully. I've had some new ones even try and break on me before getting to the 89inch lbs.
#16
Member
Posts like a V-Tak
Thread Starter
Join Date: Apr 2009
Location: Virginia
Posts: 59
Likes: 0
Received 0 Likes
on
0 Posts
Need some guidance before I break something. How in the heck do the fuel injector plugs come off? The ones with the two wires that plug into the injector? and the injectors themselves simply pull out?
#19
Member
Posts like a V-Tak
Thread Starter
Join Date: Apr 2009
Location: Virginia
Posts: 59
Likes: 0
Received 0 Likes
on
0 Posts
Backside of the engine, best pic I have at the moment, tried to get a close-up but it was way out of focus. Is this enough or should I try another pic?
#20
DINOSAURUS BOOSTUS
Expert Gearhead
Yup..new style.
The blue piece is a safety to keep the lever from moving. Pop that blue piece upward (but not too far) then the tab will push in to let it disengage from the injector. The first one is a bit of a challenge, but you'll see what'* going on once you pull that blue piece up. You can pull it out..but it'll have to go back in for reassembly.
The blue piece is a safety to keep the lever from moving. Pop that blue piece upward (but not too far) then the tab will push in to let it disengage from the injector. The first one is a bit of a challenge, but you'll see what'* going on once you pull that blue piece up. You can pull it out..but it'll have to go back in for reassembly.