Got a look at it today and definitely (as others have said) the pan needs lowering very slightly to clear the cover. It's the bit that RTV is applied to and has a lip behind it that would snag the pan if it weren't lowered.
Replacing timing chain cover on 1998 chevy 305
- Thread starter Nice98chevy
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Can't do that on the Vortec motors w/ plastic covers. The seal is non-serviceable.
OP- You will need to drop the oil pan some. Like others have mentioned, leave the rearmost bolts in and remove the fronts, allowing clearance to slip the timing cover in. If its the nice blue re-usable felpro gasket, you should be fine, but I would work some 1 minute gasket maker into the corners of the seal.
FWIW- I would not use the plastic dorman covers- Better off to use the standard stamped steel or a 2-piece if you think you'll be in there again for a cam swap or something of that nature. The seal will also be serviceable on the steel parts.
OP- You will need to drop the oil pan some. Like others have mentioned, leave the rearmost bolts in and remove the fronts, allowing clearance to slip the timing cover in. If its the nice blue re-usable felpro gasket, you should be fine, but I would work some 1 minute gasket maker into the corners of the seal.
FWIW- I would not use the plastic dorman covers- Better off to use the standard stamped steel or a 2-piece if you think you'll be in there again for a cam swap or something of that nature. The seal will also be serviceable on the steel parts.
HotWheelsBurban
Gotta have 4 doors..... Rawhide, TOTY 2023!
Is there a steel replacement cover for the Vortec? I wasn't aware one was available. I have seen someone makes a cast aluminum one, anyone have experience with these?
Thanks in advance!
Thanks in advance!
JeremyNH
I'm Awesome
@HotWheelsBurban I have the Holley aluminum timing cover on my 98 5.7L. It's fine. It's patterned after the pre-Vortecs so there are two bolt holes with ears that are missing in the Vortecs so not used. The ears are near where the water pump goes so you have to grind then off else they will interfere with seating the water pump on reassembly. I got the Holley cover after trying the Dorman plastic cover following a cam change and replacing the 4x reluctor for the 24x for cpc ignition. The Dorman leaked and the reviews on the Holley were that it wouldn't. I looked at the plastic cover when I got it off and realized my mistake. The inlaid sealing gasket stops before it goes all the way to the edge where the cover meets the oil pan. Had I hit it with a dab of rtv it wouldn't have leaked. I made sure to do that with the Holley but it has a proper gasket that looks to cover the full face so it may be that I didn't have to. If I had to do it again I probably would have stayed with the plastic Dorman but sealed it right. The Holley costs something like $75 and the Dorman less than $20. Sure you can replace the crank seal on the Holley but you'd also need a new gasket so save maybe $10 should I have to do it again but I'd still be in the hole $50. But the Holley didn't leak, it looks good, and retires plastic for metal which usually is a good thing.
And no you don't have to drop the pan. Just put the cover on at a slight angle to get it over the pan lip and then pop it into place. I would be more concerned with introducing a pan leak dropping the pan then sealing the cover lip. In any event I didn't mess with the pan either time and it wasn't an issue. You need to use a lot of rtv on the u channel under the cover because the gap is so large. By a lot I mean near the whole tube. The gap between the pan and the cover is under no pressure and the u channel forms a drip shield for the sprockets and chain above so in reality there is no real chance of leakage. If sealed poorly you may lose oil on stopping when the sump oil sloshes forward but that's about it. I'd be more concerned with moisture and debris getting in than oil getting out. But the Dorman cover I replaced looked to have a good bite on the pan from the rtv I used on it so it sealed fine. I did check with a hard stop in the driveway just to make sure it didn't puke oil and nothing so I'm certain I'm good. That was several thousand miles and no lost oil ago so declaring success. One lesson is when you pull the old cover don't just yank it free. The old gasket will stick to it and you'll start to pull it out from the pan-gap seal. So break the cover loose and use a scraper or cutting blade to cut the pan gasket before pulling the cover clear.
A1 Auto has a good Youtiube video where they cover it. Google timing chain replacement on 1998 vortec. They have a 5.7L but there's no difference. Just ignore their recommended torque values for the cover bolts unless you hope to break them and turn a pita job into a God-cursed pita job. Torque on the cover bolts is 75-100i in-lbs so 6-9 ft-lbs. A1 Auto does something like 15 ft-lbs so beware. Probably where all the "cheap bolts broke" comments on Amazon for the Dorman cover comes from.
And no you don't have to drop the pan. Just put the cover on at a slight angle to get it over the pan lip and then pop it into place. I would be more concerned with introducing a pan leak dropping the pan then sealing the cover lip. In any event I didn't mess with the pan either time and it wasn't an issue. You need to use a lot of rtv on the u channel under the cover because the gap is so large. By a lot I mean near the whole tube. The gap between the pan and the cover is under no pressure and the u channel forms a drip shield for the sprockets and chain above so in reality there is no real chance of leakage. If sealed poorly you may lose oil on stopping when the sump oil sloshes forward but that's about it. I'd be more concerned with moisture and debris getting in than oil getting out. But the Dorman cover I replaced looked to have a good bite on the pan from the rtv I used on it so it sealed fine. I did check with a hard stop in the driveway just to make sure it didn't puke oil and nothing so I'm certain I'm good. That was several thousand miles and no lost oil ago so declaring success. One lesson is when you pull the old cover don't just yank it free. The old gasket will stick to it and you'll start to pull it out from the pan-gap seal. So break the cover loose and use a scraper or cutting blade to cut the pan gasket before pulling the cover clear.
A1 Auto has a good Youtiube video where they cover it. Google timing chain replacement on 1998 vortec. They have a 5.7L but there's no difference. Just ignore their recommended torque values for the cover bolts unless you hope to break them and turn a pita job into a God-cursed pita job. Torque on the cover bolts is 75-100i in-lbs so 6-9 ft-lbs. A1 Auto does something like 15 ft-lbs so beware. Probably where all the "cheap bolts broke" comments on Amazon for the Dorman cover comes from.
Last edited:
"Dropping the pan" doesn't mean "removing the pan", which I think is clear but worth mention.
I dropped the pan on my 1998 L31 Suburban and it wasn't a terrible job. In my case, probably the most "work" was removing / fussing with the "bars" that lead from around the engine mounts down to the torque converter cover that GM added in later years for NVH reduction.
Hmm... well, wait. I seem to remember that I had to remove the right-angle oil filter adapter assembly from the block, too, and that was a PITA. The adapter came off easily enough but the gasket between the adapter and block was a major pain to remove / replace (and I assumed it should be replaced, so I did).
Again, this was all on my 1998 L31. YMMV.
Some say the timing cover can be replaced w/o dropping the pan. God Bless 'em.
I dropped the pan on my 1998 L31 Suburban and it wasn't a terrible job. In my case, probably the most "work" was removing / fussing with the "bars" that lead from around the engine mounts down to the torque converter cover that GM added in later years for NVH reduction.
Hmm... well, wait. I seem to remember that I had to remove the right-angle oil filter adapter assembly from the block, too, and that was a PITA. The adapter came off easily enough but the gasket between the adapter and block was a major pain to remove / replace (and I assumed it should be replaced, so I did).
Again, this was all on my 1998 L31. YMMV.
Some say the timing cover can be replaced w/o dropping the pan. God Bless 'em.
Good comment.
Those bolts are just shoulder bolts, so once the shoulder hits the block they're "tight"... at least in terms of them holding the cover in place. Tightening them any further only helps to keep them from backing-out at some later time.
I used a Dorman replacement cover once (on a 4.3L S10) and the "seal" between the cover and the shoulder bolts (not an O-ring but a circular seal, integral to the cover) didn't seal very well, and in later years there was some oil leakage. Had I known of this problem at the time, I would have used a little RTV during install to seal them well. It didn't leak a lot but enough to make a mess of the front of the engine, the oil pan and wherever the wind carried it.
Last edited:
Similar threads
