Hey everyone, so I have a 98 jeep wrangler that was passed down to me. It helped get my mother out of a tough situation. And it also helped me get out of a bad situation. I'm trying to do it the justice it deserves. I've replaced a handful of sensors. The intake manifold gasket 3 times, as well as some other maintenance. Now I'm on to changing the head gasket. There was coolant disappearing without a trace, and black smoke coming out of the exhaust, I had the gaskets so I took it apart.....so it has 300000 plus miles on it. This ins what I saw.(Attached files ......) Is it time for a new engine? It has a little bit of a knock with it as well. Replacing is the engine is a last resort right now due to financial constraints. This happens to be my daily driver. I'm learning to due all of this off of reading threads and you tube videos . Buying tools as I need them . Any advice would help
Opened up the head
- Thread starter Tazkm2642
- Start date
KennethS
TJ Addict
Antifreeze leaking into the combustion chamber makes white smoke, so I don’t think that was your issue. Black smoke is typically overly rich fuel.
Clean all the carbon off with a wire cup wheel, clean everything up and best you can... vacuum, blow air in bolt holes. I'd see how flat the head is with a good straight edge.
You're not much more work dropping the oil pan and rolling in new bearings. That would let you remove the pistons, inspect, clean and re-ring. Maybe run a bucky ball hone.
I'd use copper gasket spray on the head gasket to make up for lack of machining.
New head bolts. Don't forget the sealant on the front one.
Check out DexJ on YouTube...great videos on quick 4.0 refreshes.
A new timing chain and a crank pulley are good things too
-Mac
You're not much more work dropping the oil pan and rolling in new bearings. That would let you remove the pistons, inspect, clean and re-ring. Maybe run a bucky ball hone.
I'd use copper gasket spray on the head gasket to make up for lack of machining.
New head bolts. Don't forget the sealant on the front one.
Check out DexJ on YouTube...great videos on quick 4.0 refreshes.
A new timing chain and a crank pulley are good things too
-Mac
With 300k on the clock and it being this far apart, I would change out the rings, clean it up, put it back together and drive it like I rented it.
If coolant was disappearing you should take the head to a machine shop to inspect for cracks. Fo a few more bucks they could really refresh the head.
If coolant was disappearing you should take the head to a machine shop to inspect for cracks. Fo a few more bucks they could really refresh the head.
I didn't really suspect it was but with having that amount of miles on it changing all those gaskets couldn't hurt
Any advice on changing out the rings? I'm doing this in my driveway. I don't have an engine lift
See Mac’s post above. You can do a ring job in your driveway without pulling the block.
If coolant is disappearing, could be a small crack in the radiator, small crack in the heater core, or a small crack in the thermostat housing,
Doesn't look bad for 300k.
Doesn't look bad for 300k.
Since it's opened up, look at the cylinder walls first to make sure there are non-major issues. You can clean them up with WD40 and a rag, then run your fingers around and feel for any significant scratch/gouges or cracks. Anything that can catch your fingernail is likely significant and needs to be addressed before throwing new rings in. Up top there will likely be a ridge, which is normal, but it can make pulling the pistons a bitch, depending on how bad it is. You will be pulling the pistons to put new rings on. Rings will have to be filed to gap specs, just FYI.
At this point, you're pretty much doing an in frame rebuild. Before new rings, you should dress the cylinder walls with a hone. I prefer a rigid stone hone over a dingle-ball glaze-breaker for that, but both accomplish similar things.
I don’t see signs of oil burning. I do see an engine that’s running too rich….and the black smoke also indicates it.
Knocking isn’t good but could be something minor. I’d drop the pan and inspect the rods. At that point, you can decide on an inframe rebuild or not (meaning ring replacement). At 300k it’s time but honestly, the cylinders and pistons don’t look too bad from the pics. Doesn’t look like much of a ridge on the top of the cylinder but it’s hard to tell from a pic.
I’d probably check the rods for any play and if good, I’d probably put it back together as is (after a good cleaning and maybe a valve job). You need to figure out the loss of coolant and new gaskets should, if done properly, ensure you have no internal leaking coolant.
The water pump looks pretty old and kind of looks like it could be leaking. I’d be replacing that
Knocking isn’t good but could be something minor. I’d drop the pan and inspect the rods. At that point, you can decide on an inframe rebuild or not (meaning ring replacement). At 300k it’s time but honestly, the cylinders and pistons don’t look too bad from the pics. Doesn’t look like much of a ridge on the top of the cylinder but it’s hard to tell from a pic.
I’d probably check the rods for any play and if good, I’d probably put it back together as is (after a good cleaning and maybe a valve job). You need to figure out the loss of coolant and new gaskets should, if done properly, ensure you have no internal leaking coolant.
The water pump looks pretty old and kind of looks like it could be leaking. I’d be replacing that
Thank you everyone for your advice and support. I'll be cleaning out the cylinder holes and cleaning a lot of the oil and stuff off this weekend. Jobs been keeping me busy
See the comments about DeXJs on you tube.
Biggest part is you have to be methodical and organized. But you can do it in your driveway as long as it is not snowing or raining. I am capable of turning wrenches but have never done this and I would not hesitate to do so.
Okay so I pulled the oil pan off. I had the gaskets for that too and it needed replaced. It was leaking towards the front end. I'm in the process of putting everything back together and the front two rods are uneven. Heres my question, are they supposed to be exactly the same height?
Explain more or circle what your talking about.
When I hear rod I think connecting rod between the crank and piston.
I also see oil under your crank pulley. You might want to replace the pulley and it's seal too...and possibly the timing chain and it's gasket...the bottom of which is part of the oil pan gasket.
-Mac
When I hear rod I think connecting rod between the crank and piston.
I also see oil under your crank pulley. You might want to replace the pulley and it's seal too...and possibly the timing chain and it's gasket...the bottom of which is part of the oil pan gasket.
-Mac
The rods I'm talking about are the ones that are connected to the rockers. After I pulled the valve cover
KennethS
TJ Addict
The push rods ride on the camshaft lobes, and the intake lobe is offset from the exhaust lobe, so they are at different heights for most of the time. They are the same height only on the compression stroke - when the spark plug fires, the air/fuel mixture ignites, and the cylinder pressurizes - then they are at different heights again.
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