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1998 Prado 3.4 auto mystery oil leak

Commernut

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Hi Guys,
I would appreciate some input on a mystery oil leak.
During the last service (270k km) at Toyota they advised me of an oil leak and suggested I take the Prado to the steering rack specialist for further investigation. Funny thing is there is not a drop of oil on the floor where the car is parked, but the underside is wet.
The steering specialist idled the car and moved the steering wheel around while the guy in the pit checked all the seals and hose connections. They could not find any leaks and as such advised me to take it to a mechanic.
Enter the next phase: the independent mechanic cleaned the underside, because he reckoned the bottom is wet and after being cleaned it will be easier to spot where it is leaking. I drove it more than a 100kms and took the car back, put it on the lift... no leak, no sweating, nothing.
All the fluid levels were checked and re-checked and all are fine. It is now 3000km later and still no telltale leaks.
Now I wonder...should I worry and investigate it further or should I leave it and wait for it to show up again?
Your input will be much appreciated.
Cheers
Nardus
 

AdventureWagon

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I'd keep a close eye on levels and see how it goes. The power steering uses the same ATF as the transmission so perhaps it was coming from the trans? They are very easy to overfill with no leaks until you place the trans under heavy load.

Also the 5VZ engine is famed for leaking from the valve covers. I'm not sure there is one in the world without some kind of oil leak. Would be worth checking this especially if you weren't certain it was ATF.

But like I said I'd if it was mine I'd keep a weekly check on levels until I had more certainty about what was going on, including PS and engine oils. Trans too if you have the patience, it is hard to check properly though.

But if you've managed 3000km then I think you have no major issues. Just keep some fluids with you if you're going anywhere remote.
 

AdventureWagon

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Also I just remembered, when changing the oil filter on the 5VZ the oil runs out of the filter onto the bash plate and tends to stay there. Perhaps it's the mechanic noticed?
 

goodoldboy

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All the fluid levels were checked and re-checked and all are fine. It is now 3000km later and still no telltale leaks.
Job done , don't worry about it.As mentioned above it could be a spill or leak from somewhere else.
 

Commernut

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Thanks.
I know where the transmission dipstick is. It has a hot and a cold mark on it.
How exactly do you check the oil on this transmission?
 

Shayne

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There's a drain hole in the oil filter housing just to catch drips when you swap filters and send them down a rubber pipe so they drop into your oil change bucket . If oil changes are done quickly it will likely still drip a little when your driving again . I'd guess your location means the underside is usually coated with dust which would allow even the smallest amount of oil to travel a long way and 3000km suggests lots of oil changes .
 
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AdventureWagon

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There's a drain hole in the oil filter housing just to catch drips when you swap filters and send them down a rubber pipe so they drop into your oil change bucket . If oil changes are done quickly it will likely still drip a little when your driving again . I'd guess your location means the underside is usually coated with dust which would allow even the smallest amount of oil to travel a long way and 3000km suggests lots of oil changes .
I think this is in the 1KZ, was very jealous of my mate's 120 when I saw this. At least in Australia the mkII 90s with the 3.4l 5VZ don't have this kind of filter housing.
 

AdventureWagon

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Thanks.
I know where the transmission dipstick is. It has a hot and a cold mark on it.
How exactly do you check the oil on this transmission?
First you need the engine and trans hot.
Then you have to leave the motor running and put gearbox in neutral.
Then you need to wipe, replace, then check the dipstick, the fluid should be between the upper hot marks.

Don't check with the motor not running, it will look vastly overfull. Also don't check cold, the cold markings are only there to see if the trans is safe to drive and warm up to check hot.

I find I can not get an accurate reading from the first few wipes so double check before adding or removing fluid.

Here's a great video of it. The guy also has a good teardown of an A343F.
 

Commernut

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First you need the engine and trans hot.
Then you have to leave the motor running and put gearbox in neutral.
Then you need to wipe, replace, then check the dipstick, the fluid should be between the upper hot marks.

Don't check with the motor not running, it will look vastly overfull. Also don't check cold, the cold markings are only there to see if the trans is safe to drive and warm up to check hot.

I find I can not get an accurate reading from the first few wipes so double check before adding or removing fluid.

Here's a great video of it. The guy also has a good teardown of an A343F.
Very clear, thank you.
 
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