Hey everyone,

alright I’ve got quite a conundrum here. So I bought an auto 1998 C5 a month ago not running. Previous owner is second owner and he owned the car for 1000 miles car has 285k miles and all original. His story is that he drove somewhere and parked it then came out and the car wouldn’t start. Towed it home and let it sit for a year before selling it to me. I get a genuine vibe from him so I want to believe that’s true, but him back up and he stands by his story, 65 year old old-school guy so I feel like it’s what happened.

The car had a dead battery so I used my jumper pack and I would just get starter clicking. So I put a new battery thinking my pack didn’t have enough juice to jump it. I turn the key and same thing but it slowly starts to turn the engine. Vrrr…… vrrrrrr…… vrrrrr. And it fires up!

But instantly it’s making all kinds of clunking and clanking sounds and dies within 2 seconds. I’m hesitate to try it again but I do and starter clicks and that’s it no turning.

ive heard rod knock, I’ve heard lifter tick, this didn’t sound like either, maybe both actually, but across like 3 cylinders all at the same time. Rod knock amd lifter tick across multiple culminates doesn’t line up with the parked the car and it wouldn’t fire back up story.

I got the valve covers off today and rockers and pushrods looked fine, no play. Valve springs looked fine, no breaks.

I’ve got all the tools I need for a full tear down and an inspection camera. I’d like to avoid as much unnecessary work as possible. Because of both time and unnecessary money spent. Anyone have ideas on what to look at next as likely culprit? Timing chain? Lifters? Rods? Something completely different? Starter won’t turn engine but I can turn it by hand.

I appreciate all info and help.

 

Starter not turning engine but you can turn engine from crank pulley bolt?

Could the starter be shot and the starter gear was hitting flywheel/flexplate teeth making all that noise?

Also have read where sometimes the starter bolts can break the engine block on the LS1 engine.

Can you get to starter and see if bolts are tight, then maybe remove starter and try a new one, I could be way off here, but if you shop around might not be too expensive.

Then try again.

Maybe pull spark plugs out and use scope tool to look inside each cylinder for damage.

The fact that you can turn engine over by hand seems so much better than a seized up engine.

Maybe others will have more ideas.

Guess you could even just pull starter motor and see if a parts store can test it.

 

Also where do you live, might be another Corvette person here on Corvette Forum that is close to you and could help out.

Also welcome to the Corvette Forum!

 

I've heard fuel injectors make knocking sounds before so check those and make sure they aren't causing a no fuel issue too.

 

I’ve checked the starter bolts because I’ve also heard the same. Changing the starter may not be a bad idea but the sounds I heard felt like they were top end. I could be wrong though since I was in the driver seat. But worth a shot so I’ll order a quality one tomorrow. I’d be stoked to have it be the starter. I peeked in a few of the spark plug holes with the boroscope and everything looked normal to me, I’ll finish checking the rest this week. I’m in the San Diego area

I haven’t checked the injectors but I do have a spare rail with injectors from an 80k Ss Camaro. I’ll give that a go if the starter doesn’t help much.

 

Just to be safe I would definitely drain out fuel tank new filter and fuel, Maybe add a little transmission fluid to the oil and pull the fuel pump fuse While you crank the motor over With a new starter or battery just to build oil pressure in the lifters that many miles and it sitting so long I'd bet money some of the clatter your hearing is from empty collapsed lifters. Which isn't a difficult job It's relatively inexpensive to get some ls 7 lifters and ls2 retainer cups if u infact need to change em out . I think I would be taking the oil filter off cutting it open to see what kind of shavings lurk in there. if you find any broken pieces of iron or chunks of aluminum there is no sense in wasting time With lifters or fuel injectors. One thing you need to keep in mind these aluminium motors reflect sound like you wouldn't believe a spun rod bearing Sounds like tapping on the bottom of the intake manifold almost impossible to figure out where the noise is coming from exactly. That's quite a bit of miles on that engine you could get a junkyard 5.3 motor thats ready to swap in for less money than even a cylinder head refresh lifters and gaskets oil pump etc respectively. Take a peek at that harmonic balancer when you have it running Make sure it's not rubbin on the steering rack causing ruckus as well
Also welcome to the forums good luck sir

 

Thanks, forum feels welcoming and helpful already.

Doing the fuel dump and fill seems like a good idea too, gonna need it at some point anyway. So I’ll order a filter and fill up some jugs with 91.

as for the lifters, I may try your trick to build some pressure in them when I get a new starter on. But if they’re bad and I do a tear down it’s gonna be a whole lot of refreshing. Definitely a rabbit hole of “may as well do this and that while I’m in here”

I’ll cut up the filter when I’m home to better point in a direction.

as for the 5.3 swap, I have an lq9 sitting in my garage. But I’m not sure how I can get it to pass ca smog on a 98 car I get both ecu scan and the sniffer out here. If there’s a way to pass it easily without having to look for a shop that takes the $400 handshake deal, I’d be all over it. Maybe y’all know something I don’t about that. I do have an ls2 intake to slap on it to make to look appropriate. But I’m not knowledgeable on the 6.0 with 5.7 ecu and pass smog deal.

 

I would suggest making sure critical friction points are well oiled before screwing around too much, as you know, these motors don't have a way to spin the oil pump without actually running the engine. I am not a man to insult another by implying dishonesty, but it is a used car, and one wouldn't want to spin dry crank bearings , which might already be a little tired, or screw up the top end if in fact, the time stored got away from the guy, or the story got confused somehow.

I think the suggested fuel change is a good place to start, I would probably replace the entire fuel filter assembly, given the age of the car, you are probably not leaving much money on the table by not squeezing the last miles out of that thing. and it would allow you to eliminate one possible concern for probably the time you own the car.i

It could be the starter got some corrosion from sitting around, and you might now have the motor brushes sitting on a section with problems, after the first spin. I have never had this problem on any car, nor have I used the suggested repair, but have read many post suggesting a sharp tap to the starter body, usually with the aid of a wooden dowel, like a broom handle, is useful. Personally, I am more of a take it out and look at it guy, but this pound on the starter is a popular suggestion, with reports of success.

Some just over fill the crank case to oil the main bearings after a long sit. To my surprise, I have an outboard oil pump to pre oil prior to start up, which I can run in through the oil lines I extended out when I relocated the oil pressure sender. which, at least, sounds easy.

 

Moved to C5 Tech.

 

Thank you vetteman for moving this to where it should be.

lots of good advice here and definitely knowledge people giving it.
i pulled the oil filter and cut it open with some shears and was stoked to find no metal or bearing bits inside just some oil gunk.
Great, now to be sure my startup didn’t cause any major wear issues I decided to drain the oil to check the drain plug magnet and the oil for metal. Happy to report no oil. But sad to report that 4 quarts of dexcool came out first. Well ****. Noob mistake not draining the oil before doing any further diagnosis, nothing on oil cap or dipstick led me to think i had coolant in oil but that’s what I get I guess.

So this has me thinking all the clunking and crazy banging sounds I heard was probably the oil pickup trying to lubricarte the engine with de cool for the 2 seconds it was running before it died. No compression likely cause of no start. I’m just hoping a cylinder didn’t have coolant in it and was running on a compression stroke and fucked itself when it ran for 2 seconds. I’ll find out soon I guess.

debating dropping a 60k motor for 2k in it or pulling this one and sending it out for a full proper rebuild bottom to top. Both run about the same with me pulling and installing motor.

what do y’all think?

 

Almost bought the Harbor Freight leak down tester for my old truck that was running like crap, but found the carb was just flooding the engine big time, in the middle of putting Edelbrock Pro Flo 4 fuel injection on the old 396 big block Chevy in my 1965 C10 shortbed truck.

I think you should buy the leak down tester, unless you have one already, see if using it will tell you how coolant got into oil pan.

Blown head gasket, cracked head or block.

What if, and I'm going way out, what if someone didn't know what they were doing and put coolant in the oil fill?

I think the leak down tester is where to start, I think you can tell if intake valves leak, exhaust valves, blown head gasket.

Take cap off coolant surge tank and with leak down tester in each cylinder listen for air, or zip tie a rubber glove over the threaded part the coolant pressure cap screws on, see if glove builds pressure.

 

Good idea, reminds me of a time I did an engine swap on a Volvo because I saw milky oil in the coolant reservoir only to find out later that the milkiness came from transmission oil having broke through the radiator trans cooler passage into the coolant. That was a fun lesson learned.

i dont have a leakdown tester yet but I’ve got one on order now. Considering all the rockers are out, all valves should be closed so this gonn make the test a bit easier. I’ll report back what I come to find from the test and what I decide to do from there.

no start condition has me thinking there’s some serious compression issues somewhere, Or multiple places.