Overheated 5.2 Dilemma

[jswhiteknight]

I've got a 1997 Ram 1500 4x4 with the 5.2 magnum motor with roughly 223,000 miles. Its been feeling down on power for some time but still ran ok. It overheated on a pretty hot day and I wasnt checking my temp gauge so I'm not sure how long the gauge was sitting at H before it stalled. It blew all the coolant out of the rad overflow bottle. After it had cooled (several hours) it fired back up with no noise and sounded normal besides having no coolant.

I did a compression check on the driver side with all cylinders being between 150-160 psi. Passenger side had the blown gasket on cyl 2 and 4. I removed the heads and took them to a machine shop and he told me they were cracked (not surprised. lol) and quoted me $450 per head for new ones.

Now here's my question. Would it be worth just sticking new heads on and putting it back together or should I suspect there to be other issues further in the block? I can still see crosshatch marks in all the bores and still had its usual oil pressure.

I'm torn between just sticking a junk yard motor in it for $450(with around 200,000 miles from what they told me and that doesn't sit well with me). Just as a temporary fix being its my daily driver and pull the rest of the original motor and go though it and replace the worn out stuff as time and money allow OR just hope for the best and reassemble it.

When I pulled the intake it had a very noticeable and bad burning oil smell (which would be expected) but did make me worry about the rest of the engine.

Sorry for the wall of text but I just wanted to give enough info.

 

[dapepper9]

Judging by the condition of your comp check on the driverside i would probably just slap it back together. The cracks are extremely extremely rarely detrimental or noticeable performance wise. If it's just a driver/work truck i wouldn't be all that worried

 

[dapepper9]

At least, as long as the original head isn't warped. If it is, slap a new one on and go

 

[EvilSpirit]

I think a little extra prep work increases your chance of success.

Obviously the deck and heads have to be flat for much chance of success. Personally I'm not a fan of using the scotchbrite style discs for final head surface prep - they leave a polished surface which is too smooth for OEM style gaskets (on iron block/head applications). While I may use them for a first step, I go over the deck and heads with a sanding block with some 220 to lightly scuff the surface and give the gaskets something to bite into. Key word is LIGHTLY - you are leaving a surface finish, not decking the block/heads LOL.

I'd use premium composite head gaskets, like FelPro's, over the cheapie RockAuto economy ones. Clean bolt holes and lube threads to insure accurate torques. I would not put the intake back on without resealing the plenium cover - again, premium gasket over cheapies, and make sure the bolts do not bottom out. Premium sealants, like Right Stuff over cheap silicon.

At 200K, and since the heads got hot, if I had the ability to install new valve seals I would do so.

Hope your repair goes well.

 

[Hero6]

$450 per head? Are these brand new heads or ones that the machine shop reworked? My son needed a head for his 97 5.2, picked one up at the local machine shop that was reworked on their shelf for $150 ( Dover Cylinder Head, Panama City Fl.)

 

[McBroom]

$450 per head? Are these brand new heads or ones that the machine shop reworked? My son needed a head for his 97 5.2, picked one up at the local machine shop that was reworked on their shelf for $150 ( Dover Cylinder Head, Panama City Fl.)

Lol I know some of the guys in that shop. It’s been a long minute since I’ve been there but those are a good group of people there.


The Blue Mule

 

[McBroom]

Prep is king!!
Best to clean the bottom of the intake make it look like new.
It’d be nice n helpful to if we coul see pictures of said cracks. Because location of the cracks are key in helping you with the problem.


The Blue Mule

 

[SportRam00]

I'd probably just check the heads for warping and throw new gaskets on it an be done. Usually the heads/head gaskets take the brunt of engine overheating. It would also be good to find the cause of the overheating as well. Water pump and thermostat replacement come to mind. And while you're in there replacing the water pump, may as well throw a new timing set on it.

 

[jswhiteknight]

It was $450 for a new head. The crack i saw was in between the intake and exhaust valves on the drivers side head and that was warped. I didn't get to see the cracks the machine shop found on the blown gasket side be he said there were multiple cracks and far worse then the drivers side. I didn't take pictures. I'm pretty sure (but not positive) it overheated from it being 95 degrees that day and I was bucking a 40mph wind and the engine was revving from 1800 to 3000 rpms and back down to 1800 for about an hour because the cruise control wasn't maintaining speed (possible vacuum leak.). I didn't even know of the plenum issue until a month or so before it overheated. Seems like it may have been a contributing factor to my power problems.

I am leaning more towards just getting new heads and sticking new gaskets on anything and everything that I can get to with the engine halfway pulled apart, along with a new water pump and fan clutch and thermostat and making sure there isn't anything plugging up the radiator.

Is it possible to replace the rear seal without unbolting any of the mains? I have a bad oil pan gasket and have to pull that off too and I figured being i'm in there I should check that out. I also plan on checking the timing chain being I have oil leaking at the bottom half of the timing cover.

Thanks for all the tips so far and and if there is anything I should check out before reassembly please let me know. I'm always willing to learn something new.

 

[SportRam00]

I believe you can replace the rear main seal with out unbolting the mains. You may have to loosen a couple to get at the top piece if you can't shove it through and pull it out with some sort of tool.

I need to add oil pan gasket and rear main seal to my list as well. Not really leaking terribly, but still leaking a little. My oil pan gasket looks terrible though, but so far is just seeping oil. I'm too lazy to pull it a part right now.

 

[McBroom]

Time to get an Edelbrock top end kit with cam n lifters. The cheapest and most power for the dollar


The Blue Mule

 

[SportRam00]

I'm not sure how much you trust eBay, but there are multiple stores on there that sell new/rebuilt heads for good prices. Obviously, you won't be getting Edelbrock performance/quality, but they would probably work if you're on a budget.

 

[dapepper9]

Rear main will need the rear cap removed yeah.