Thread: TD5 oil cooler return pipe blanked off? D2a

Just checked the RAVE dvd, and if that is indeed hose 7, feeding into pipe 6, it is an important part of the system, to do with cooling water to the fuel cooler. I suggest you get a RAVE dvd, check cooling system component layout, 26-1-2, then operation, coolant flow, engine warmup/ cooling flow, engine hot, 26-1-11 . Hose 7, feeding into pipe 6, supplies water to the bottom section of the radiator, which is a separate tank, with a hose from the tank delivering cooling water to the fuel cooler. Water flow thru the cooler happens when a thermostat on the back end of the cooler opens after the fuel reaches temp., water then flows from the cooler to the heater matrix behind the dash, then to the top radiator hose. [ by the way, i'm no expert, just reading the printout I took from the dvd to try to educate myself, and will stand corrected if I have it wrong, but I think I have it right] Bob.

Great reply Bob, that's how I read it now from the workshop manual. I'll have a gander tomorrow at the radiator to fuel cooler connections and see what's there. I've certainly had no temp issues in the 3000kms since I've had the car, but it has not been that hot.

I am curious to know if anyone has heard of this mod - and why.

Originally Posted by stallie

"I am curious to know if anyone has heard of this mod - and why".

I'm curious as well, the only thing I can think of is if there had been a leak in the heater matrix, or heater hoses, and someone thought that hose 7 was just part of the heater system. How that would affect the fuel system is a mystery to me, but I know when I go on a long run, the fuel tank gets warm with the cooler in operation, taking the cooler out of the setup could only increase the temp. . I will study the RAVE dvd this arvo., and if any thing obvious stands out, will let you know.Any other hoses blanked off in the fuel cooler setup?. Perhaps one of the more knowledgeable members might have an answer .Cheers, Bob.

I've had a good rummage as best I can without taking the radiator and EGR etc out and a bit more of a read with manual in one hand and engine in the other.

The coolant is meant to go from the oil cooler return pipe on the LHS of the engine block (item 8 on the 26-1-2) through short stepped pipe (7) around the back of the engine through pipe6.

Then it's meant to go through pip 37 to the EGR cooler - (which incidentally I don't have) then a return pipe 35&6 to the coolant tank (which I don't have either).

My EGR is a pipe straight from the manifold to the EGR valve, with no cooler in place.

The pipes from the fuel cooler to/from heater, coolant tank and radiator all seem to be OK.

Now interestingly in my rummages, I notice I don't have an intercooler or gearbox oil cooler (mine is a manual). I read in another thread that these were not delivered on UK models.

Could I have a UK import....? Are UK D2a's all missing the oil cooler return pipe and the intercooler and gearbox oil cooler?

Had another read of my notes, and the flow is not quite what I thought. Water flows from hose 7, to pipe 6, to the bottom tank of the radiator, [ hose 22] to the front of the fuel cooler [ hose 23] ,out to hose33, to hose 27, to hose 30, to the water pump.The "T" piece at the back of the fuel cooler has a thermostat that opens at 82 degrees "c", allowing entry of water from the heater. If you have a cooling system coolant diagram, it makes it clearer.Reading the description of the cooling system operation, it certainly is a complicated system, and I'm getting a headache trying to understand it. What I cant understand in your situation is how you dont have a massive coolant leak with that hose blanked off, i dont think there are any non-return valves in the system. Sorry I cant help further, would really like to know the outcome of your investigation. Bob

Ok, I've got a 2001 TD5 110

I removed the EGR including the EGR water cooler and plumbing.

Now the water pipe that runs from the oil cooler on the LHS to the RHS on vehicles not fitted with the EGR water cooler has a rubber hose that picks up a spigot on the bottom rear of the radiator.

Vehicles fitted with the EGR water cooler have various hoses eventually leading back to a four way connector just below the coolant reservoir.

When I pulled my EGR water cooler off I converted it to the non water cooled setup. This required the replacement of the four way connector under the reservoir with a three way. Removing the radiator and drilling out the unused bottom spigot on the radiator to take the coolant pipe from metal coolant pipe to the lower radiator. It also required the heater hose to be replaced with a standard heater hose (standard diameter).

(See the insert on the RAV CD for the early EGR systems)

If the previous owner of yours has blanked off the coolant line from the oil cooler then he has either replaced the four way connector under the reservoir with a three way or blanked off one of the spigots.

I'm not sure that the mode done on yours is affecting the fuel cooler. as on the water cooled EGR's the return line goes to the four way connector not the radiator.

If this is the case then apart from the means of capping off the coolant line on the oil cooler (LHS) it would seem to be an effective fix for removing obsolete piping.

My concern would more be the loss of cooling function for the oil cooler. Not sure if having blocked the coolant flow from the oil cooler how this affects oil cooling. Is there a coolant bypass in the oil cooler?

Bob, we must be reading different versions of the RAVE workshop manual! Your numbers don't correlate to mine (hose 23 is the large dia 90 degree bend off the rad on mine to the thermostat housing and hose 22 goes from the rad to the fuel cooler). Copy of my page attached.

Scott, No bypass of any sort that I can see.

Looking closely at the version I have, I am missing parts:

7 - short hose pipe
6 - oil cooler return pipe
37 - Hose to EGR cooler
34 - EGR cooler
35 & 36 - EGR cooler connecting hose.

Or as it seems I have a pre EU3 model (based on the EGR setup) I am missing pipes 7, 39 and 38.

My EGR appears to be a type 1 EGR.

It states that only a small %age of the coolant goes from the oil cooler to the rad then the fuel cooler so I am wondering if there would be any impact on the oil temp at all?

I am starting to get more concerned about the lack of intercooler and gearbox oil cooler though....

Intercooler question.

Where do your air hoses run?
Air box->Turbo->???? (normily intercooler).