Major Engine Failure

[Jay88]

Hello,
My names Jay, I'm based in New Zealand & have had a horror time with my newly bought Ford Explorer. I'm hoping that one of you guys might be able to advise how the following could have happened to my beautiful new truck

My truck was purchased only in March 2020 just before NZ went into lockdown. She has only 62,000 kms (40,000 miles approx) on the clock. We had her independently checked by a specialist that conducted compression checks etc on her & she passed with flying colours!

Since purchase, we have only travelled less than 1,000 kms. 3 weeks ago I went to start her up & she sounded like a tractor!! We called the AA out and they stated that she might have cracked head! That the truck wasn't drivable & needed to be taken to a local garage. As she was being pulled onto the tow truck, coolant poured out of the exhaust!!

The garage finally removed the heads a couple of days ago & yesterday I managed to take some photos of the engine.

As you can see from these pics, piston 5 & 6 have large pieces broken off!! Nobody over here can give us any explanation as to why a truck with only 62,000 kms on the clock would have such a massive failure! Our new truck is now dead & we're left paying for a truck we can't use

Any advise from you guys who I know are really experts on all things Explorer would be greatly appreciated.


Jay Collins

 

[Rick]

My guess is that the timing chain skipped and the valves hit the pistons. I'm not positive though, since I'm not sure where the contact point for the valves would be on the SOHC. The timing chains usually don't go bad with such low mileage. Very odd for sure.

 

[94Eddie]

I second the timing chains and/or guides causing this problem. At this point it really doesn't matter what happened. The engine is probably done for and not worth salvaging. I agree with Rick in that this is unusual for to happen on a 4.0L V6 with this low mileage on it.

 

[Gmctyphoon]

That’s a very nice looking truck. I’m sorry that happened.

The whole engine is toast and At this point you need to get another one. As long as the rest of the truck is in awesome shape cosmetically and mechanically then I would put a reman engine in it. But a used junkyard engine will be cheaper.

 

[drdoom]

Hard to speculate without seeing the heads...

 

[Josef161]

Hard to speculate without seeing the heads...

My engine is probably on it's way out due to a timing chain rattle and i would prefer to put a used engine in the explorer. Could you tell me what are the most important things to check on the 4.0 liter sohc and how to check them (like how can i check the head (through the oil fill hole or through the spark plug holes)... Thank you so much.

 

[94Eddie]

My engine is probably on it's way out due to a timing chain rattle and i would prefer to put a used engine in the explorer. Could you tell me what are the most important things to check on the 4.0 liter sohc and how to check them (like how can i check the head (through the oil fill hole or through the spark plug holes)... Thank you so much.

I recommend installing new timing chains/guides into whatever used engine you install. Otherwise, the odds are good you will see the same issue in the near future.

 

[imp]

My guess is that the timing chain skipped and the valves hit the pistons. I'm not positive though, since I'm not sure where the contact point for the valves would be on the SOHC. The timing chains usually don't go bad with such low mileage. Very odd for sure.

The SOHC is said to be NON-INTERFERENCE. As such, the timing of valve motion, broken or skipped chain cannot cause piston/valve interference, IF it's non-interference design. The broken off land on the piston is likely a fluke in manufacturing, possibly heat treating.

 

[tedmc1]

The SOHC is said to be NON-INTERFERENCE. As such, the timing of valve motion, broken or skipped chain cannot cause piston/valve interference, IF it's non-interference design. The broken off land on the piston is likely a fluke in manufacturing, possibly heat treating.

I made that mistake thinking that too. The 4.0 OHV was non-interference.The 4.0 SOHC is INTERFERENCE. I'va asked the question as to how many teeth does the timing chain need to jump before a valve could actually make contact with the top of a piston. No answers to that question.

 

[drdoom]

I made that mistake thinking that too. The 4.0 OHV was non-interference.The 4.0 SOHC is INTERFERENCE. I'va asked the question as to how many teeth does the timing chain need to jump before a valve could actually make contact with the top of a piston. No answers to that question.

I have confirmed that a one tooth jump will damage the valve cover but not the valves. Not an answer, I know.

 

[Gary Crist]

Do they have ethanol in your fuel, down there?
Kind of looks like it pinged itself to death.

A chunk of piston, valve, etc. can jump from cylinder to cylinder
and hit every one of them and never exit the engine!

 

[sandsprayer]

Nice looking truck!

Hard to speculate without seeing the heads...

Do they have ethanol in your fuel, down there?
Kind of looks like it pinged itself to death.

A chunk of piston, valve, etc. can jump from cylinder to cylinder
and hit every one of them and never exit the engine!

There has been detonation, a picture of the heads and valves will tell more of the story.
Low mileage, maybe the injectors got gummy sitting so much.
That sucks

 

[drdoom]

Nice looking truck!




There has been detonation, a picture of the heads and valves will tell more of the story.
Low mileage, maybe the injectors got gummy sitting so much.
That sucks

In the one image, it looks like the cassettes are intact...

 

[drdoom]

Cylinders and rings could have rusted in storage.

 

[drdoom]

I wonder what the engine oil looked like.

 

[MisterWizard]

Do they have ethanol in your fuel, down there?
Kind of looks like it pinged itself to death.

A chunk of piston, valve, etc. can jump from cylinder to cylinder
and hit every one of them and never exit the engine!

That was gonna be my guess. It doesn't look like impact damage, there are no other marks on the tops of the pistons, and the fact that the damage occurred at the outer edge of the piston, right over the top ring groove, makes me suspect serious detonation blew the tops of those two pistons off.
The coolant out the exhaust probably means the head suffered similar damage into a water jacket.
+1 for a reman motor, it is a strikingly clean looking truck with really low miles for its age.

 

[Jay88]

Hi,

I wonder what the engine oil looked like.

The engine oil was lovely and black! until she was pulled onto the tow truck and coolant stated pouring out. Once the heads where pulled, the engine oil was the black milky colour!!

 

[Jay88]

That was gonna be my guess. It doesn't look like impact damage, there are no other marks on the tops of the pistons, and the fact that the damage occurred at the outer edge of the piston, right over the top ring groove, makes me suspect serious detonation blew the tops of those two pistons off.
The coolant out the exhaust probably means the head suffered similar damage into a water jacket.
+1 for a reman motor, it is a strikingly clean looking truck with really low miles for its age.

Hi,

The truck was a repo... and we think she had been sat in a barn for a couple of years!! It does make us wonder if the engine is an original!! As a lot of low mileage trucks come from Japan onto the New Zealand market. Kiwi's love changing engines over!!! Th rest of the truck looks in mint condition after we had her groomed and serviced. she had only travelled 1,076 kms from purchase (think its just over 500 miles) I dont understand how such a failure may have occurred to such a young engine?

Do you know if there is a way to check the engine numbers to see if it has the original engine fitted, I've got the VIN and Engine Numbers.

 

[Jay88]

Cylinders and rings could have rusted in storage.

Hi,

We think she sat in storage for a couple of years, she was imported in from Japan, which is typical here in New Zealand. We get about 80% of our second hand vehicles from Japan as most have low mileage on them.

 

[Jay88]

In the one image, it looks like the cassettes are intact...

Yes we think she's been in storage (barn) for a couple of years!!