TD5 and cooling systems.

[nedflanders]

Right bit long winded and hope it makes sense.
I've got a TD5 90 about 11 Years old which I brought with us from the UK and the cooling system had never been serviced apart from a coolant change when I bought it. So thought I'd do a bit of an overhaul including a new thermostat, waterpump, radiator and remove the plumbing and coolerfor the EGR.
Radiator was from PWR and is a lovely bit of kit with a claimed 30% larger capacity.
Normally the pipe from the oil cooler runs round the back of the engine and into the EGR cooler, this I rerouted to an opening on the bottom of the new radiator, the same as the pre-egr cooler TD5's. The rest is as standard.
Now LR list the thermostat as opening about 82C and fully open at 96C.

Took it for a long run and max temp I saw on the nanocom was 82c heading up a long big hill but running temp was about 74C. Spent ages before driving bleeding the system and heater works OK (but takes ages to get heat now)

Now question is, I've seen a few TD5's where the pipe coming out of the oil cooler is removed, if I did this would it increase running temp as it seems to be overcooling now. From what I can gather the pipe from the oil cooler is basically a bypass so the thermostat can't do it's job as it's allowing engine coolant a route straight into the radiator before the coolant has heated up enough to open the thermostat.

Thoughts and please correct me if I'm wrong ;)

Edit: I also have a block temp gauge that measures head temp and this is confirming the engine is running considerably cooler now.

[jimr1]

Hi , I've also got a td5 , when I look at the plumbing , and follow the heating hoses . They go around the engine bay , into this and that . I've thought why do I need all this ? OK top and bottom hose , with branches going to the heater . A bypass through the stat ok as well . But there is lot going on that just doesn't look necessary . There was someone on here that took them all out , just to make It basic , that was a while back . Jim

[Tombie]

Engine can only overcool if the Thermostat is staying open..

[nedflanders]

Its a new thermostat that was tested prior to installation, Looking at the old radiator the pipe that runs from the back of the oil cooler to the bottom of the Radiator is blanked off at the radiator, also the radiator outlet for the fuel cooler is restricted. I'll blank off the oil cooler out let and fit a restrictor in the fuel cooler line and see if that helps.
At the minute there is a free passage of coolant into the radiator from both the oil cooler and fuel cooler bypassing the thermostat.

[quaddrive]

Yes if you are partially bypassing the thermostat with the oil cooler hoses etc now then it will overcool with the larger radiator. Had this with my TD5 previously.

Cheers

[nedflanders]

Got the blanking caps for the oil cooler pipe and ordered the restricter for the fuel cooler pipe, will see what shes running at then :)

[nedflanders]

Quick update, fitted the blanking caps to the oil cooler outlet and removed the pipe and blanked off the corresponding inlet on the PWR radiator.
Fitted a restrictor into the fuel cooler outlet and now running temp is back to normal, 88-92deg and the heater gets warm again.
On a side note the PWR radiator is a top quality bit of kit, they have no listings for the TD5 but the PUMA radiator is the same. There was a couple of brackets that aren't needed that needed cutting off to fit the allisport intercooler but it doesn't take long and is well worth the effort, plus they build to order and actually deliver when they say they will.
:)

Oh one more question, has anyone actually monitored what temperature the coolant is when their Viscous fan kicks in?, after failing I changed mine for a genuine one but have never heard the 'whooshing' like the old one (it's never overheated since changing though)

[PhilipA]

AFAIR with mine its about 94-96C.
Regards Philip A