Hey all, I am trying to confirm some suspicions of an oil leak I have been chasing that has progressively gotten worse. Initially, when looking up from under, and also when I remove the top wiper cowl, it appears to be coming from just under the timing chain tensioner where the timing cover, head, and block meet. At first I thought it was the tensioner leaking so I ordered the gasket from Toyota, replaced it, cleaned the engine and thought it was fixed. When the leak continued and it began to be cold with lots of snow, someone suggested using ATP205 to see if that helped, it didn't, I honestly think that it made the leak worse. Now that area just under the tensioner is where the trail of oil starts, but it is to the point that if we drive it around town normally, after a month it goes from the top of the full mark on the dipstick to the bottom. Now that it is starting to warm up and a friend of mine is going to let me use his shop to do the repair I am looking for some second opinions on a platform that I am not familiar with, I normally rebuild motorcycles and work on my car. I am thinking that the sealant on the timing cover has given out and it needs to be resealed, the oil is only leaking from that side and the car has just under 190k miles on the clock. Any thoughts?
Pretty common. Usually its the crankshaft pg sensor.. Don't use any leak sealer that just makes a mess and more trouble.. After you have some more posts you can access the SEARCH FORUMS link up top and search any malady. I searched for you check these posts out for more info: https://priuschat.com/search/409023927/?q=oil+leak+timing+cover&t=post&o=relevance
I believe that if the timing cover is going to leak it usually happens where head meets block and it's bc there is a divet that caulking blows out of. Most often it's the oil press switch. If it's the drain bolt turbulent air sprays the droplets everywhere and u will be confused by the source.
I believe that if the timing cover is going to leak it usually happens where head meets block and it's bc there is a divet that caulking blows out of. Most often it's the oil press switch. If it's the drain bolt turbulent air sprays the droplets everywhere and u will be confused by the source.
Occasionally its the oil pressure switch. 98% of the time its the rtv sealant they use to seal the timing chain cover. Generally not enough where different parts of the block meet under the seal. On the block when installing the timing chain cover, sealant is used at the seams On the inside of the cover, sealant is used around the perimeter with extra where the cover will meet the block seams Dealers often want 14 hours plus parts. By the book the job pulls the engine. Independents may do it in the car. Many people just watch their oil level and forget it until the head gasket blows and the cover has to come off for that work. Which unfortunately is becoming more common as gen3s age. Gasketmasters hg video started at timing chain cover install. Time 28:00-35:00. Form In Place Gasket used by Gasketmasters Permatex 82180 Ultra Black RTV Sealant Used on inside of cover and allowed to set for a few minutes prior to install. Also GMasters does not appear to temporarily install other assemblies like motor mount per Toyota.
By the 2010 with 300k right now that's not been off the road long enough to address this problem It looks like it's coming out of the where the plastic meets the metal on the oil switch sticks out of the timing cover towards the firewall when I clean it off and let it rip for another month it gets a vapor all over that side of the cover but the oil goes down almost none very little in a month of driving for all the driving services that she runs It May go down to halfway maybe and then it's usually about time to be changing the oil It's so minimal I've just let it go giving the conditions the cars being used under I'll probably get a switch this week or next and put it on the next time the car sitting long enough
Fix it when you replace the head gasket. If you haven't replaced the gasket by now, then have whoever replaces your engine replace the timing chain cover gasket before they put it in the car. Otherwise? If the leak, seep, weep, or whatever isn't a major contributor to a 1q/3000 mile drinking habit, I'd fugetaboudit...... ACTUAL mileage will vary.
Some thoughts, for DIY reapplication of sealant, with the engine in place: 1. The only sealant application on the engine face would be at the 3 engine "split-lines"; it's much more practical to apply the rest to the cover (loose, off the engine). 2. When putting the sealant on the cover, instead of trying to follow the above drafting excercise, just go a little thicker in split-line zones (that's more-or-less what it's trying to say). 3. Using a compatible but longer-curing sealant is advantageous. Gasket Masters has a recommendation in their videos. 4. Watch Gasket Master's application technique; it's not bad. Instead of trying to achieve a bead with certain diameter (mimic the robotic applicator employed at the factory), just go along the proscribed route, putting frequent dabs, then spread/join them with a finger. 5. Do study the above route carefully, don't overlook or misplace any of the sealant zones. Disclaimer: I've never done this.
That is what the procedure instructs. They also specify a different sealant for the seams and want a two hour cure before starting the engine. Gasketmasters takes some procedural liberties and uses Permatex 82180.
Pretty much necessity for any post-factory timing chain cover install? The Repair Manual spec's a form-in-place gasket with a very short cure time, and stipulates: 1. The cover should be back on within 3 minutes of applying seal packing. 2.All the bolts (25 by my count) should be in and torqued (to varying torque values), along with the engine mount and oil filter bracket, within 15 minutes.
It appears they may not put any sealant on the block and may also allow the rtv on the cover some set time before installation. It is likely their choice of sealant provides some flexibility and perhaps it is a couple of hours before startup. If it works it works, plus they do a head gasket and timing chain seal for less than most dealers will reseal the cover alone.
Yeah I don't think Gasket Masters are even aware of that split-line application. I'd be inclined to apply the engine split-line beads of sealant on the split lines themselves, the rest on the (loose) cover. I think Toyota's rationale is that oil can seep into the split-line, then do an end-run 'round the sealant on perimeter of the cover. Permatex Ultra-Black install instruction says it takes 24 hours to "fully cure, at 70F with 50% relative humidity, longer in cold weather". Probably safest to delay even adding oil for 24 hours. https://www.permatex.com/products/gasketing/black-gasket-makers/permatex-ultra-black-rtv-silicone-gasket-maker-5-oz/
In the video GM points out the seam and warns it must be cleaned and sealed on both sides. But he just adds more rtv at the corresponding positions on the cover. To be fair the video at that point cuts straight to the cover installed and partially bolted down.
I was planning on replacing the head gasket at the same time as preventative, but would you recommend replacing the head bolts? And if so, what brand? I have been trying to figure that out the past couple of days and everyone seems to say different things.
The repair manual has instruction for assessing the current head bolts, for reuse. Still, sentiment here is for a DIY’r, the risk of bolt failure outweighs the price of just using new. For lack of more insight, I’d go with the Toyota bolts. Part numbers for the bolts, and a complete gasket kit, are in the attachment.
The cheap way is to reuse the bolts. The downside is they may stretch with resulting loosening. Then the head gasket fails again. I have seen it. Like everything in life, there is a risk reward relationship. Your choice. I am not sure I would do a preventative head gasket. Maybe a rebuild including pistons and rings if it was burning oil. Its not a given you will have a failure in your ownership. Statistics indicate only 3% are still on the road at 200k miles.
