How does a grille block improve warmup time?

[PaleMelanesian]

All the discussion sounds good and theoretically sound. I'll throw in some numbers. On my daily commute, over the same 11.2 miles, different days, both starting at 57 degrees F.

No grille block, final water temperature 154F, for a rise of 97 degrees
Full grille block, final water temperature 195F, for a rise of 135 degrees

Similar results for other temperatures, but I picked 2 that were most comparable.

[MetroMPG]

Leave it to an empiricist to ruin a good debate!

(Thanks for posting that. )

[diesel_john]

MetroMPG you did this thread post #4. (hot fuel)


With 90w in my trans. it feels like someone put peanut butter in there over night till it warms up. That can't be good.

[MetroMPG]

Ah! Thanks, diesel_john. I thought I was going nuts. I remembered (wrongly) it being in the first post of the thread. Thanks.

I wouldn't recommend anyone do anything outside of their owner's manual. But if it were my car, I'd be trying something lighter than 90w. (And I'd have a replacement transmission on a shelf in the garage :-P)

[rbhollabaugh]

I've driven Citroens all my life. Some of the cars from the 60's had an option of a manually operated flapper that closed air off going to the radiator. The air to the radiator and the rest of the engine compartment was via a somewhat sealed duct straight from the grill to the radiator. The flap was in this duct and was operated by a cable from the driver's seat. When the flap is closed the engine warms up quite a bit faster on a winter day. So, yes it does work. But in this case the downside was that if you forgot to open the flap the engine would overheat.

Rich

[MetroMPG]

Hi Rich -

I've read the same thing about older Volvos that were sold in the Canadian market.

While on the topic of variable grilles, I trust everyone's seen this thread:

Video: active aero (grille block) via shape memory alloy

[dremd]

Originally Posted by MetroMPG

Ah! Thanks, diesel_john. I thought I was going nuts. I remembered (wrongly) it being in the first post of the thread. Thanks.

I wouldn't recommend anyone do anything outside of their owner's manual. But if it were my car, I'd be trying something lighter than 90w. (And I'd have a replacement transmission on a shelf in the garage :-P)

Take a look at this thread http://forums.tdiclub.com/showthread.php?t=132884
you'll see that all 90w oils are actually the same viscosity. Worth a peak.

[Frank Lee]

Originally Posted by AndrewJ

True, but that cold coolant has to go into the engine sometime. Think of it this way: Its 32 (F) outside and you're driving around, your coolant in the radiator cools down to 15 degrees (F) if you have a just-warmed-up-engine you probably don't want to send 15 degree (F) coolant coursing through it. It won't help. If you can keep that coolant from cooling down in the radiator you'll get into closed loop faster.

This here talk about radiator juice getting colder than ambient temp has got me all corn fused.

[MetroMPG]

Originally Posted by dremd

Take a look at this thread http://forums.tdiclub.com/showthread.php?t=132884
you'll see that all 90w oils are actually the same viscosity. Worth a peak.

Actually, I meant that if it were my car, I'd probably use a numerically lower weight oil than 90. In other words, I'd ignore the owner's manual recommendation (because I had a spare transmission on a shelf in the garage).

Frank: I was wondering when someone was going to pick up on that. Only people (OK, and the wee animals etc.) feel "wind chill". Machines can only get as cold as the ambient temp, regardless of the icy breezes whistling past.

[dremd]

MetroMPG
I didn't mean to demean your post; I was actually trying to give it a boost by showing that thinner oils can pass as thicker ones without anyone noticing.
Regardless; if you are concerned about thin oils run redline it is much thinner and tons of performance guys run it with no issues.