Tdi 300 getting warm again

[swivelrat]

I probably fang the Ol girl a little hard up green mount each day but the temp needle is creeping again, only now and then but it's bloody winter. I know it's testing things and if I take things easy I won't have prob but why hide the inevitable. New four core rad and the rest that gets wet bar the head. New viscous hub did the trick last summer, but im wondering if head is telling me something I don't want to know. Doesn't use any green stuff yet but does worry me.

So me thinking radiator cools coolant that keeps motor bits melting with compression ignition when reunited with cooler coolant, cool!

Say at normal running, I'm guessing that thermostat is not fully open so that when the pressures on or the daily temp is over 38, the system has the capacity to compensate? Or at normal running, is thermostat fully open and additional demand on cooling system is met by what as I can't figure what else helps out.
I'm also thinking that viscous fan should only be necessary in hard slog under low vehicle speed? I've tested prescribed thermostat opens at temp stated but should I invest in one that opens at a lower temp to see if cures issue?

Curiosity cause of insomnia

[rick130]

According to Tridon, the t/stat takes 10-14* after crack point to fully open so you are going to get some temperature glide under load, even in cooler conditions.

I have a new HD Redback core in mine and it's getting up to 95* crossing the range here ATM.
If the hill was longer the temp would either stabilise or possibly come back as the t/stat opened more.

The big problem wth the Defender engine bay is getting the air out.
A vent in the guard/s helps here, as the air appears to struggle to get past the underside of the engine/gearbox/t/case.
Uninformed cut a nice size vent in the LH guard and it works well, dropping the running temps in his testing as the HD core didn't seem to do much.

Replacing the fan clutch and noting a difference in running temp at 80-100km/h confirms this theory IMO

[Defendozer]

96884

I've also added a LH side guard vent to my Tdi (hopefully the photo works from my phone)!
I haven't driven it all that much since but I would say it has made a difference of maybe a couple of degrees, you can definitely feel warm air flowing out if you put your hand over it anyway..
The pic is from before I painted the grill black and I also painted the footwell just so it wasn't really standout white behind the vent.

[swivelrat]

Thanks for replies, all points raised seem valid. I can appreciate the air flow issue, you can get your dam arms in there alone getting large volumes of hot air going down then out at reasonable rate.


The t/stat maybe having issues adjusting to load I guess, will remove and run some tests although it works fine getting eng temp from cold to norm quick enough.


I might also look into a second temp sender and gauge set up. Does anyone have any experience in correct placement and brand(redarc?) I could stick one in radiator but would prefer pre t/stat to monitor engine temp if ready made threaded hole into water jacket exists.


Cheers

[jboot51]

The brass/plastic plug in the thermostat housing is pre-thermostat.
I have used a mechanical gauge at that point.
Just need to be cautious as too long a probe will touch the bypass plunger on the thermostat.


There is also a plug on the head, top/passengers side.
Not sure of its purpose, but it is a waterway.

[SSmith]

New viscous hub did the trick last summer

For such a quick and easy test, id be making sure you didnt get a dud, wouldnt be the first.

Sent from my GT-S7562L using AULRO mobile app

[Pacemaker]

On a defender the viscous fan hub issue will only be apparent at speeds of 80 km hr plus. Anything under that speed and you wont get the engine overly hot with the cooling system in good condition.
I also cut a large hole in my guard. It made very little difference to the engine temp but the passenger floor doesnt get as hot now. The mesh covering the hole gets really hot after a highway run