How to diagnose a leaking gasket?

drichardson90

New member
I have a 2000 4runner Ltd 3.4L and changed my oil about 3 weeks ago. I smelled burning oil and check my oil level, which was below the min level. Took a look at the filter and drain plug, as I have had leaks there before, but didn't appear that the leak was coming from there.

I look higher up and saw the there was a ton of oil leaking from above the oil pan (see pics). I have no idea how to diagnose the leak to locate the source. I have read a lot of valve cover gaskets & head gaskets leaking, but don't know how one is able to tell which it is, or if it's something else.

Can someone please help me figure out how to diagnose this leak? I don't know the difference between the head gasket & valve cover gasket, so I can't figure out which it is. Where are those gaskets located?

I know me posting this may anger some users, but I have searched this forum and elsewhere online to figure this out and haven't found much help. Thanks for any help.
 

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Also, here are a couple more pics from what appears to be the source of the leak. These pics were taken on the drivers side underneath the drain pan (looks like the side of the engine). I'm wondering if these are the valve covers?
 

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More than likely that would be a valve cover oil leak. The oil is probably leaking from the round plug seals at the back of the v/c. The leak seems to be higher than the head gasket. I just replaced my v/c gaskets. You could confirm by cleaning up the oil then driving and look to see where it's wet with oil.
 
More than likely that would be a valve cover oil leak. The oil is probably leaking from the round plug seals at the back of the v/c. The leak seems to be higher than the head gasket. I just replaced my v/c gaskets. You could confirm by cleaning up the oil then driving and look to see where it's wet with oil.

Thanks for the info, do you have a pic of where the v/c & head gaskets are located?
 
that brings up a good question. I too have leaky valve cover gaskets, while replacing plugs and wires I snugged down valve cover bolts hoping that would suffice. now my question is with the way sparkplugs are down in those holes would it be safe to spray degreaser and blast away with the hose???do those rubber caps covering the sparkplug wells seal well enough?
 
You need to replace the head gaskets and and clean inside engine I had the same problem with my 4Runner 4cyl & v6 the engine is dirty inside they need to change the position gasket and change clean throttle body buy OEM. Engine gasket replacement, replace fuel filter and injectors, fuel system cleaning, replace both hoses, radiator cap, new anti freeze. Spark plug cables, and spark plug, thermostat and all the rubber tubes need to be placed. I will estimate about $1,000 - $1,100 on the dealership and your truck will become a brand new truck but the mechanic will not know how to repair because there is special tools. But mechanic will charge from $950 -$1,300 Toyota dealer is cheaper to repair. n inside of the engine. It caused for putting FRAM oil filter is aftermarket, put genuine Toyota oil filter for now on after the service. You could put any type of motor oil except filters. If you have a garage in your home you could do it by your self buy genuine gasket to prevent leaking.i had the same issue with my v6 and 4cyl and your truck will turn to a refurbished 4Runner.
 
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You need to replace the head gaskets and and clean inside engine I had the same problem with my 4Runner 4cyl & v6 the engine is dirty inside they need to change the position gasket and change clean throttle body buy OEM. Engine gasket replacement, replace fuel filter and injectors, fuel system cleaning, replace both hoses, radiator cap, new anti freeze. Spark plug cables, and spark plug, thermostat and all the rubber tubes need to be placed. I will estimate about $1,000 - $1,100 on the dealership and your truck will become a brand new truck but the mechanic will not know how to repair because there is special tools. But mechanic will charge from $950 -$1,300 Toyota dealer is cheaper to repair. n inside of the engine. It caused for putting FRAM oil filter is aftermarket, put genuine Toyota oil filter for now on after the service. You could put any type of motor oil except filters. If you have a garage in your home you could do it by your self buy genuine gasket to prevent leaking.i had the same issue with my v6 and 4cyl and your truck will turn to a refurbished 4Runner.

Stop telling people to replace head gaskets.
 
You don't what Shut the F--U--C--K Up! You're not helping him I have 2 F--U--C--K--E--N 4runners had the same issue.

Okay..........
I think the only reason he said that is because someone might read your post and think their HG is leaking when you meant VC gasket, I'm sure. Very common problem with the 4runners
 
You have no idea what you're talking about!

Ok i am a Toyota mechanic for 20 years in north Hollywood service I have 2 4runners. the pictures I could Idiagnose the issue. Four cam 24 engines has the problem it's not new to me. Everyday I work most of these engines because they have beyond 160,000 miles. 3rz engines is easy to repair because the engine is smaller. If you have any question of the issue contact me I am a Toyota mechanic. Look if he doesn't fixed the issue the engine will start burning and needs to replace the engine.
Here is the deal
Pay $1,000 the fixed the entire issue in Toyota service
Or pay $4,000 - $5,000 for engine replacement that's simple.
I tell many customers to have a choise
The truck will become refurbished as 0 miles no leaks and problem for the next 15 to 20 years
 
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Ok i am a Toyota mechanic for 20 years in north Hollywood service I have 2 4runners. the pictures I could Idiagnose the issue. Four cam 24 engines has the problem it's not new to me. Everyday I work most of these engines because they have beyond 160,000 miles. 3rz engines is easy to repair because the engine is smaller. If you have any question of the issue contact me I am a Toyota mechanic. Look if he doesn't fixed the issue the engine will start burning and needs to replace the engine.
Here is the deal
Pay $1,000 the fixed the entire issue in Toyota service
Or pay $4,000 - $5,000 for engine replacement that's simple.
I tell many customers to have a choise
The truck will become refurbished as 0 miles no leaks and problem for the next 15 to 20 years
Burning oil happens more likely as a result of failed valve stem seals, and even more commonly, piston rings. Head gaskets can indeed allow oil into the combustion chamber, but given its viscosity it is more likely coolant will enter the chamber first.
Saying that a vehicle can be considered refurbished with just gasket service is foolish. A machine shop should service both cylinder heads, deck and check the gasket face, r+r the valves and valve seats and so on. Then, the block cylinder walls should be checked, and serviced should it fail visual inspection.
Saying that an oil leak is the head gasket is the easy answer. It is something I see mechanics diagnose all the time because they can't be assed to spend futher inspection time. I believe the op's issue is the valve cover gaskets; a quick Google search will show that this happens all the time to the 5vz-fe.
Lastly, its ridiculous for.you to assume you know it's the head gaskets by just looking at the picture. I don't see compression check numbers, or a leak down test result, or even a visual check on oil in the water.

To.the OP: Your best offense is getting the engine super clean of all residue. Then, you should be able to track the beginning of the leak, possibly even without the UV leak detection dye.
 
Ok i am a Toyota mechanic for 20 years in north Hollywood service I have 2 4runners. the pictures I could Idiagnose the issue. Four cam 24 engines has the problem it's not new to me. Everyday I work most of these engines because they have beyond 160,000 miles. 3rz engines is easy to repair because the engine is smaller. If you have any question of the issue contact me I am a Toyota mechanic. Look if he doesn't fixed the issue the engine will start burning and needs to replace the engine.
Here is the deal
Pay $1,000 the fixed the entire issue in Toyota service
Or pay $4,000 - $5,000 for engine replacement that's simple.
I tell many customers to have a choise
The truck will become refurbished as 0 miles no leaks and problem for the next 15 to 20 years
If you're a 20 year Toyota mechanic, then I'm the God damn king of England. See, we can both make shit up.

You don't what Shut the F--U--C--K Up! You're not helping him I have 2 F--U--C--K--E--N 4runners had the same issue.
I hope you get banned.
 
Look for oil behind the valve cover gaskets. If it is wet then change them, cam plug seals, pull the semi circular plugs and reseal them with Toyotá's RTV Form In Place Gasket. I'd start here if they are original.

It could be the oil cooler gaskets as well (the thing that says Toyota 6025 on it). A real PITA to change.

Not the head gaskets by any stretch. Keep an eye on the oil level.
 
You don't what Shut the F--U--C--K Up! You're not helping him I have 2 F--U--C--K--E--N 4runners had the same issue.

Wow.
Ok i am a Toyota mechanic for 20 years in north Hollywood service I have 2 4runners. the pictures I could Idiagnose the issue. Four cam 24 engines has the problem it's not new to me. Everyday I work most of these engines because they have beyond 160,000 miles. 3rz engines is easy to repair because the engine is smaller. If you have any question of the issue contact me I am a Toyota mechanic. Look if he doesn't fixed the issue the engine will start burning and needs to replace the engine.
Here is the deal
Pay $1,000 the fixed the entire issue in Toyota service
Or pay $4,000 - $5,000 for engine replacement that's simple.
I tell many customers to have a choise
The truck will become refurbished as 0 miles no leaks and problem for the next 15 to 20 years

Yeah, sorry, I'm not buying it.

Based on your numerous questions about basic things regarding automobiles, you are not a "Toyota Mechanic".

There's nothing wrong with not being a Mechanic. But giving bad advice under the guise of being a Mechanic, isn't cool.

No "20 year Toyota Mechanic" would ask this: http://www.toyota-4runner.org/3rd-gen-t4rs/174192-what-ect-overdrive-3rz-engine-4runner.html
 
Wow.


Yeah, sorry, I'm not buying it.

Based on your numerous questions about basic things regarding automobiles, you are not a "Toyota Mechanic".

There's nothing wrong with not being a Mechanic. But giving bad advice under the guise of being a Mechanic, isn't cool.

No "20 year Toyota Mechanic" would ask this: http://www.toyota-4runner.org/3rd-gen-t4rs/174192-what-ect-overdrive-3rz-engine-4runner.html

As I mentioned in the other thread he's spouting nonsense, you can't forget his thread asking if swapping grilles and tail lights is illegal.
 
From experience with these 3rd gen if in fact the oil is coming from the head gasket, the conclusion I have had most often happen is the head is crack on the passenger side rear corner and replacing the head gasket is a waste of time. Its not unheard for this to happen more common in 97 year model, that was the year most commonly occurred but rare. The crack is hairline and very hard to detect under typical inspection. Typical test used was the UV dye option or removing the heads and doing mag fluxing to the head itself.
 

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