All the experts and gurus,

I am new to this forum. Recently I bought 1 unit of 1997 Toyota Prado Tz 3.0cc diesel (this is Asian model of toyota prado) and found that the engine oil leaked. I have no idea on how severe the leakage could be as the previous owner had had his engine thoroughly cleanned before selling the car. Please refer the photo on my prado engine condition. The mechanic advised me to overhaul the engine which i think it could be too much if the leakage is only a minor problem.

Do you think I need an top overhaul? Can any gurus here help to diagnose the leak problem? thanks.

I imported my Surf about 6 years ago (same engine), and at that time it had 87,000km on the clock, it's now got 175,000km and has always looked like that, was told that it was the turbo seals leaking and that it needed a rebuild, but after looking at other motors they all looked the same, so apart from cleaning it down every service I have not done anything, so my advice is leave it alone.

hello mate
The Gold rule says -- the diesel engine mustbe dry/clean and a bit rusted without any leaks traces.
You had to ask for advise before car purchasing ---it is abnormal when the engine shines brightly when sold.
Now you are face to face with this problem to locate a leaks spots. So firsly the engine has to be cleanned to mark all leaks origination.
After, it is understood you have to repair these spots either by means or rebuilding ot just gaskets changing using high temp silicone sealant.
Cheers/Igor

Its a bit hard to tell from the pic,but it looks as if it maybe coming from the air intake. You need to clean it up and watch as the oil leaks to see exacty where its coming from.
You could also remove the air intake and inspect it for fresh oil

Im not sure what "overhaul"means,it can mean different things to different people. I wouldnt tust a mechanic that uses such vague terms,he should give you an exact description of the problem and an extent of the work he will carry out.
Without that,it will be like an open cheque.

hello mate
the problem of oil in the intake pipe confirms that the seals of turbocharger's bearings are worn down and part of the same oil is penetrated there instead of draining in the sump. (i do not conside too much gases outgoing from the crankase due to engine worn down as whole)Cheers/Igor

Hi igormus,
Thanks for your comments. If this happens to be true, is that mean I just need to change the bearing seals of the turbocharger? This is only a minor repair, am i right?

Hi sandgroper,

What is normally meant by "overhaul" in your opinion? According to the mechanic, he will open out the crankcase, change cylinder liners, piston rings, and recondition the cylinder wall (thus will become biggers after doing that)..... I wonder whether my prado need to undergo such big surgery or not....

Hello bwsy2002
It's better to have turbocharger overhauled ---> to be dismantled + bearings change + oil seals change + cleaning + statically ans dinamically ballanced (rotor) + cleaning of course. Good luck/Igor

I dont really have one,in my opinion it is usually associated with dodgy practices,sounds good but its rubbery.

These dont have cylinder liners,so how can he be replacing them?Toyota havent used liners since the early 80s in the 2H diesel.
Normally you would just bore out the cylinder to the next over size and this means new pistons ,not just rings.You can fit liners if the bore is badly worn or scored.
What is on offer from this mechanic is what is good for him,90% labour and 10% in parts. Its an old trick and a short term fix,it will be blowing oil again in 6-12 months, even if that was the problem originally.


You need to get some more opinions and ask the mechanic why he has come to the conclusions of what he is suggesting
The fellow that you have been dealing with should have done a compression test as a minimum before offering to partially rebuild the engine
Im betting its turbo seals also,this is like a $1000 job in oz,cheaper if you remove and replace the turbo

If it does need a rebuild ,the engine needs to come out and have an engine kit put through it as well as machining all parts that need it. This would mean new bearings ,seals,gasket,pistons,rings.
That kind of job is best left to places that specialise in full engine rebuilds with diesel experience.

Im not a mechanic but I have gone through this 3-4 times with various engines inc Toyota diesels over the last 20 years.
Ive also had 2 friends who have had this"in body rebuilds" and both were extremely unhappy with the result when they found out ,for a little more,they could have had a full engine reconditioning.

This is what my Surf looks like, same engine and same place with oil, it has been like this for the last 6 years, I just give it a clean when I do a service, so leave it alone as long as the engines running ok.

all the intake hoses suffer from a bit off oil due to breather pipe pressure and a bit leakage from the turbo seals
better leave alone and just keep it clean now and then unless you got your own bank

Hi Andy and tspirit888,

I am deeply thankful to your advices and photo shown by Andy. My worried has been eased by looking at your photo, and the statement that the engine is still ok with that condition for the past 6 years.

Therefore, I shall follow your advice to leave it alone until there is more severe leakage.

Andy, do you need to top up the engine oil from time to time? Can the engine oil last for 5000km distance running without topping up from time to time? It seems your engine leaks more severely than mine.

Hi sandgroper,

Appreciate your opinion and I learn some precious knowledge. I agree with you that the overhaul might not solve the leakage problem. As some of the forumers here advise me not to have the engine overhauled until it becomes more severe, what is your opinion?

Hi All the Gurus,

Please advice if I need to change my radiator (pls refer to the photo uploaded). My mechanic recommended I to change it as the fibre plastic of the radiator has deteriorated at the bottom (becoming pearl white color instead of the original brown color).

What is the consequences that I may face if the radiator leaks?

Appreciate all of your precious comments. thanks

Hi sandgroper,
May I know what is meant by recondition the engine? how is it different from rebuild or overhaul?

I change the oil and filters around 5k and have only once had to top up, not because of the leak it was just that maybe I didn't put enough in on the service, and then it was only a small amount.

Two things can happen with the radiator, and one is a water leak which will cause overheating, the other is only if it is an Auto gearbox, becuase the auto transmission cooler is in the bottom of the rad, and if that splits water will enter the gearbox and it will cost mega bucks to repair.

I do think that your mechanic is after most of your money, he seems to be looking at worst case on everything he see's, so by all means get the rad pressure tested and if ok just enjoy driving one of the most reliable motors made.

It may well mean the same thing if you are dealing with genuine people ,but I would never confuse reconditioning with an in body parts replacement consisting of replacing the rings
But you really need to ask the mechanic or person exactly what they they are offering.

Hi Andy,
Thanks for the advice.
But I wonder how to get the rad pressure tested?
Will the pressure test detect any failure of the material deterioration? (what i mean is, the test may show the rad is still ok to use, but when time comes, could the plastic rad just fail without any sign?)
And when it leaks. how does the water mixed with the gearbox coolants? Are they sharing same pipes? Mine one is with auto gearbox.

Radiator shops have a hand pump which plugs into the radiator after removing the radiaitor cap. The pump has a guage and the pressure is increased to simulate normal radiator pressure and they then look and listen for leaks.
It wont necessarily find material deteriation unless it begins to leak where the material is degraded.
We used one to find the water pump leaking on my Holden last week

How the coolant and oil can mix depends on the construction of the radiator. Some have metal pipes inside the radiator and as long as they are not broken or corroded the coolant and oil cannot mix
Others ,like my old Volvo empty the oil into the bottom of the radiator in a seperate compartment and if the barrier is broken or degraded ,they can mix.

The best way is to fit a transmission cooler(like a small radiator) and keep it separate from the radiator,this is what I did on the Volvo

Hi, sandgroper
Thank you so much on the informative advice.

I wonder if all the cars with autogear box have the radiator shared by transmission system and engine? Or is it just particulary for Toyota Prado?

By the way, I wonder if I can install a seperate cooler for my auto transmission as the engine compartment is very compact already. A new seperate cooler means a dedicated cooler fan, circulating system and etc.....

May I know if there any sign on radiator to indicate the car owner of potential leakage problem?

I would say all cars have them



You can install them to the front of the radiator. Radiator shops have special plastic clips to hold them to the radiator core




Usually the leaks start off too small to notice and it will lose pressure. So if your hoses do not go hard after 10 mins of driving,you either have leak or you need a new radiator cap.
If you allow small leaks to go unfixed and the coolant turns brown,then it will be corroding on the inside.

Hi all,

My rad cap finally breaks. photo attached here. Luckily it never boils my engine head. As for the auto trasmission oil, I saw the oil was still in dark color and not milky, so I am quite confident the aluminium pipe for auto trasmission oil is still in good condition and rad water never mix with oil. Thanks God.