Question for your Wide-grille guys in Cold places

[SnakeyesTx]

So, its 33 degrees outside (0*C). First time I've driven my car in cold weather since I've owned it... and I have an over-cooling problem!

In normal weather the heater works fantastic. Tonight, I let the car idle in the driveway for 30 minutes. The temperature needle got close to 1/2. As soon as I drove off about 2 miles, enough arctic air passed through the front end to drop the temperature back down into the blue! Naturally, my heater was cold as hell.

I did roll the steptronic dial to full hot and the temp dials to full hot like I did in warmer weather, and the heater was pretty weak; maybe 50-60 (10-15*C)degrees at best. I was wondering if the snouts on our wide grilles really let that much more air pass through the front end to chill down the radiator and engine enough to do this.

As a quick-fix solution, I'm thinking about making some grille covers like 18-wheelers do to limit the amount of air that gets passed through. Has anyone else had to do this or is there something else going on making me run super cool in cold weather? As stated before, everything works just fine in warmer weather... like about 55-60 degrees plus. (12-15*C for you metric folks)

[Fetch]

I'm thinking it's your thermostat.

If anybody knows the reason 18-wheelers have the radiator covers I would be really interested in that. I was under the impression that diesels ran much colder than gas and had a harder time keeping warm in the winter even with a functioning thermostat?

[angrypancake]

wait waht does this have to do with wide grill, except another reason to bash on it cause its ugly? (all in jest, I swear!)

[SnakeyesTx]

Well, the wide openings up front seem to have this huge open area for air to easily pass through. I know the narrows have the horizontal ones next to the verticals, but is it the same wide void right behind them?

I guess I forgot to mention that a new factory thermostat went in as the new motor was going in last month too. Not sure if its defective since if it was open enough to never really let the motor warm up fully, I would assume that it would creep higher in temperature back when our weather was a lot warmer since it wouldn't keep the water in the radiator long enough to really cool down since its cycling around more.

[Traian]

Without fins (surface area), i don't think cold air passing over the engine has much cooling effect. Air passing through the grille should be only for the radiator, which shouldn't be receiving coolant if your engine is going into the blue and if your thermostat is working.

If you really want to be safe tho, tape a piece of cardboard over it and paint a Benz logo on there like the vans do hehe.

[colo525i]

My guess is stuck thermostat, i was out in 0F (-17c) weather the other night and had nice toasty heat even on the highway. I know i only have the narrow grille, but another 32F cooler has to make up for the difference. I was surprised to take the car out in the first really icy conditions here this year, and it did quite well. good snows FTW

[Tron5]

I´m also guessing it´s the thermostat that is faulty. I had a similar problem with temp only barely creeping out of the blue mark, only when really applying gas it would reach the 1/2 way mark. As a consuequence getting little or no heat inside the cabin.
I changed the thermostat and all was well, found out that it wasn´t closing properly.
The ambient temperature around here is between 0-8 C.

[brick8]

It was 11F here this morning. The temperature gauge was right in the middle but the heater was blowing cool air even when the steptronic was set all the way to the right. Don't know what I will do when it really gets cold outside.

[92E34]

Actually Diesels run hotter than gasoline engines. That and Diesels do not like to start when its cold out and take forever to warm up. In germany they never shut down any of their diesels in the wintertime.

Instead of making some fancy pants thing what you can do is this. Loosen the top of the radiator. Slip one piece of cardboard in between the radiator and the body. Make sure it is approximately 75% the size of the radiator. Re attach the radiator.

[Qube]

No way in heck it's overcooling at 0c. I vote for T-Stat if it intermittently works. Sure, I have narrow grill, but have been in -45c (with windchill) rock solid in centerline temps.