Thread: Defender 300TDI Water to Air Intercooler

Originally Posted by slug_burner

Your water cooled IC would always be at thermostat temperature or higher after the car warmed up. I think you will find that the temps that you get on the outlet of the IC will not be as good as they could be.

Yeah, after I posted that comment I revisited the figures and thought that the best I could get was a 10 - 20.C reduction in air temp before the air reached the A/A IC. Thats with the car operating at 80-90.C and the air from the turbo blasting out at 110.C

Hi Guys,
Sorry for my tardiness in finishing this saga, but I keep getting distracted by shiny things.
I fitted the extra Temp Tx to the Turbo discharge and got these figures out on the freeway;
105-110kph
400-450DegC EGT
0.7b (ish..) Charge Air
115-120DegC Charge Air before cooler
60DegC Charge Air after cooler
55DegC Coolant
27DegC Ambient

On full boost, under heavy load, the Charge Air before cooler gets up to 145-150DegC. I don't know if this is normal, or if its an indicator of the relative health of my turbo.

On the journey home from this run, all the temperatures went through the roof as the coolant boiled out. When I was able to suss it out and refill, I found a lot of black oily residue in the coolant, that could only have come from the turbo. Fearing I'd punctured the heat exchanger core with that last Temp Tx, I pulled everything apart for good look.

To my relief, I couldn't find anything wrong with the new intercooler. I now reckon that there was an blockage in the old intercooler, that was finally dislodged by circulating hotwater through it for a couple of weeks. I had been in the routine of flushing the intercooler each year, or so. But it just goes to show how hard it is to clean these things properly.

I took the opportunity to clean up and simplify the plumbing, while I was re-installing everything. And because I didn't know what else to do with it, I installed the 9" radiator I bought with the intercooler, in series with the original intercooler/radiator. This worked pretty good.

Whether it's the blockage removed from the old intercooler, or the extra little radiator mounted in front of the engine radiator, but everything now is running much cooler. For the same highway run, I get the figures;

105-110kph
400-450DegC EGT
0.7b (ish..) Charge Air
115-120DegC Charge Air before cooler
53DegC Charge Air after cooler
45DegC Coolant
27DegC Ambient

Under all load conditions, the cooler is achieving better than 50% cooling - until the ambient gets up into the high thirties and I try climbing big hills at highway speeds.

The coolant temp usually stays in the forties, rarely getting above 55DegC. That's just another reason no one should consider using the engine coolant in the IC circuit.

The performance was so good, I've started to undo some of the injector pump tweeks I've been doing over the years. Now, I've got engine performance that's a bit better than it was, and fuel economy of a little over 10L/100k's

I hope this helps someone.
Cheers,
Bud.