My brother has a 1988 Toyota mini truck with the 22R-E engine, an engine I am not very familiar with. He has been unable to get the timing cover to stop leaking a phenomenal amount of oil. The oil seems to be coming from the top of the timing cover, where the timing cover mates to the head. The second time he took it apart to attempt to cure this leak, he cleaned and applied RTV (“the right stuff” in the cheese whiz can) to both sides of the head gasket, hoping that it would seal, but it seems to be leaking worse this time around. Has anyone ever successfully made this repair without pulling the head? He thinks that will inevitably be the next step, but would rather not pull the head for obvious reasons and is hoping to hear good news from someone who has seen this and can provide a method to seal this that does not require pulling the head. He will pull the head if necessary, but is hoping someone has a method that will work that does not require this additional expense and labor. Also, he knows about the bolt length issue (no two bolts on the timing cover are the same length, apparently) and kept that in order, so he did not switch any bolts.
A leaking valve cover doesn’t require head removal. The leak is either from damage to the cover, or something else leaking. Are you sure it’s leaking at the gasket?
It’s the timing cover leaking, as in the cover at the front of the engine that covers the timing chain and serves as a location for the water pump to mount to, not the valve cover. Oil is quite literally flowing from the top of the timing cover, at the seam where it meets the cylinder head. On this engine, the head gasket protrudes past the deck of the block and onto the timing cover, with a single bolt installed through the head and into the timing cover. He theorized that the head gasket was not allowing the timing cover to seal properly and hoped that the RTV would fill in any gaps. He has consulted some Toyota 4X4 forums on the matter and has been getting mixed answers, some saying it can be done without pulling the head or oil pan (I was surprised he got it off the engine without removing the oil pan, but it seems there is quite a gap at both ends, which is why RTV is recommended instead of a traditional gasket) and others saying the only “good” way to seal the timing cover is to remove the head and reinstall it with the timing cover in place. I just decided to ask here to see if anyone has seen this and found an effective way to correct this short of pulling the head, which others say is the only “good” way.
I have no experience w/that engine, but on my Corolla – which has a timing belt rather than a chain – a leak sometimes appears that looks like it is coming from that spot. But it is really the valve cover gasket that is leaking. It sound like you are sure where it is leaking, and the engine in question has a timing chain so it may be a different situation for how the oil is contained, but if you have doubt, it’s worth it to check for sure that it isn’t the valve cover that is the source.
On my Corolla, when you install the valve cover gasket, according to the shop manual, you are also supposed to dab some RTV sealant at a couple locations where the gasket just doesn’t make a tight enough seal. One of those locations is right directly above the timing cover. There’s a little u-shaped depression for the camshaft. There is where it will leak if you don’t apply the RTV. When I had a similar oil leak on my Corolla, all I did to fix it was replace the valve cover gaskets and apply the RTV sealant at the shop manual recommended places, and no more leaks.
There is no oil that high up on the engine. It is quite literally flowing out from the top of the timing cover, between the timing cover and the cylinder head. In fact, I looked at his work before he installed the valve cover, radiator, fan, etc. and it looked promising. I was surprised that it leaked and disappointed that it leaked as much as it did. It runs down the timing cover and drips onto the ground at a rate of about one drop per second with the engine running.
The oil is most likely being slung off the chain against the side of the toming cover. A leak at the head gasket would need to be a serious crack to allow that much unpressurized oil to seep through. Did he allow the RTV to cure before starting it up? Most RTV requires as much as 24 hrs to cure, thicker applications requiring more time. I’ve personally never used ‘Right Stuff’, and prefer to use the tube stuff. My favorite is Permatex Blue RTV. On a clean gasket application, I’ll us it right away. On a no-gasket application, I let it cure overnight.
I just had a thought. How did he get that cheez whiz stuff on the top of the headgasket? Did he bend the gasket down? I’ll bet he may have put a crease in the headgasket right at the junction of the head, timing cover, and block. Perfect place for a leak like you describe. A new headgasket may be the best cure. It’s actually not such a bad job on these trucks.
Did he reinstall the bolt in front of the timing chain that goes straight down through the head into the timing cover? Was the t-cover closely inspected for a crack around that bolt hole?
He may want to pull the oil pan, then try to slide the t-cover up to the head and try again. Other than that, looks like it’s time to pull the head.
Mark: I didn’t know it was possible to r/r an “R” series timing chain cover without removing the head. Or, maybe one has to remove the head to replace the chain? I have a 1979 Celica, (20R) and the first step listed in the manual is to remove the head when removing timing chain cover (page 4-20 of the 1979 Celica FSM).
Was the cover removed for a chain replacement, or was it just leaking (and you’re repairing a leak)?
Anyway, were there gaskets to be replaced? On the 20R engine, the FSM lists two of them, and they go over the dowels. The timing cover bolts are torqued to 7-11 ft/lb.
Sorry I can’t help more.
I read ‘timing cover’ and thought ‘valve cover’…here’s an idea - is there unusual pressure in the crankcase? Is there a lot of blowby? Maybe the PCV system is plugged and the pressure is making the leak worse.
I talked to him today. He said he noticed a crack around the top bolt hole, the one that goes through the head and into the timing cover, and had filled it with RTV and hoped for the best. I also think he had damaged the head gasket during preparation for reassembly, and he does too, especially given how much it was leaking. Blowby shouldn’t be an issue since the engine was rebuilt recently by the previous owner (he did a pretty slick paint job on it, too, red and silver). PCV system seems to be functioning normally. I would attribute the significance of the leak to the proximity to the camshaft. Oil tends to get slung through the bearings rather forcefully, and on some cars you can observe this by removing the oil fill cap with the engine running. If there is not a deflector in the valve cover, oil will sling out pretty forcefully, and with enough volume that it could probably empty the crankcase in an hour or so if left unchecked. Anyway, he bought a head gasket and is going to visit the U-Pull yard tomorrow morning when he gets off work to hopefully secure an undamaged timing cover so this can be done and over with. Will keep everyone posted, regardless of the results.
Update: he got a used timing cover from a salvage yard, removed the head, installed the timing cover, then installed the head with a new head gasket. This cured the leak up top, but also revealed that the oil pan gasket was leaking. Fortunately, Toyota uses a removable crossmember which makes removing the oil pan very easy (not sure this is the case on 4X4s; his is 2WD). He then found that no one had a listing for an oil pan gasket, even though there was one on the pan when he removed it. Further research revealed that Toyota redesigned the oil pan in '85 for use with RTV rather than an actual gasket, so he went that route. The engine is now completely leak-free.