diesel in the coolant, can I tell where it comes from

[Chanoo]

Hello folks,
I have deisal in the coolant overflow bottle, now it's my understanding that this can happen two ways, 1. A faulty fuel cooler 2. Some expensive issues with the fuel rail leaking inside the head.
My question is this is there a way to determine and work out which one of these methods of the fuel in the coolant is occurring?

Thanks
dave

[CraigE]

As you said likely a faulty fuel cooler.

[towe0609]

I think you can have the fuel cooler pressure tested? In theory that should either expose it as the problem, or eliminate it.

I had an experience where, according to my (then) mechanic, both the fuel cooler and head failed at the same time.

Fuel cooler and all hoses replaced (I was told the fuel coolers are available as refurbished units on an exchange basis, and the one you send back is pressure tested), only to still find diesel still getting into coolant. New AMC head and another new set of hoses later, all fixed.

I was always a bit sceptical but that was the story.

[scarry]

What engine,may help get a few more responses.

I am guessing TD5?

[Chanoo]

Oh yes sorry it's a td5
In an 02 defender

[towe0609]

I thought the head weakness was fixed in the 15p engines, so hopefully just fuel cooler

[harro]

Hello folks,
I have deisal in the coolant overflow bottle, now it's my understanding that this can happen two ways, 1. A faulty fuel cooler 2. Some expensive issues with the fuel rail leaking inside the head.
My question is this is there a way to determine and work out which one of these methods of the fuel in the coolant is occurring?

Thanks
dave

Are you sure it's diesel?
engine oil can get into the coolant via the oil cooler.
Either past a couple of o rings or a corrosion hole in the cooler itself.

Paul.