The weather dropped to -25C recently, -13F, and my car hates it. I've had the car for a year and a half now, but this is the first time I've been somewhere this cold, and it runs like a bag of sh*t till the temp gauge comes up, stuttering and loud. Then once its warmed up its still really loud under load, easily three times as loud as when the outside temp is right around freezing.

Recently replaced the plug wires, plugs, air cleaner, fuel filter, did PCV replacement 10k kms ago, running 5w20 mobil 1. Any other ideas?

 

Check the coolant temp sensor to see if it's getting out of range. If it's going bad it will either feed too much or too little fuel to the engine.

Toss in a bottle of fuel injector cleaner if you haven't yet. I'd recommend either Lucas or Chevron with techron.

If you can't find the noise take it to someone who can. When was the timing belt last replaced ?? The serpentine belt ??
You can always pull the serpentine belt off and see if the noise is gone, that would narrow it down to the belt or something it spins.

If you have a place to plug it in you could always add an engine heater. Either one that goes in a freeze plug or a tank style. Nice thing is you get the defroster and heat working sooner. It's also easier on the engine as the oil flows easier when it's warmed sooner by the warm engine. You would also have a smoother idle sooner.

 

In addition to what Kfrog suggested..

Any codes set (CEL on)?

Is your coolant strong enough to go that cold (and stay liquid)?

 

I would also like to know what kind of noise you're getting (click, clang, grinding, purrrr, bzzz or just a loud exhaust tone).

+1 for testing the coolant. If partially frozen, it may put water pump under severe load, which could lead to timing belt failure.

JPN

 

many people in cold climates put some sort of sheild in front of the radiator to block the cold air from flowing through the rad.....ive seen aluminum/plexi-glass and even temporary cardboard used..

 

Blocking the radiators air flow will not help it idle better. It will help it heat up faster IF, IF the thermostat is stuck slightly open. But you also run the risk of overheating your engine if you block off too much or forget to remove it on a nice day
If cardboard actually helps do anything on an 850 you have a problem someplace. I'm in Minnesota and it gets way below zero up here and my engine still comes up on the temp gauge to the 3 O Clock position same as a 90 degree day. Heat coming out the vents is hot.

 

You may also have some sticky lifters. Make sure you use 91+ octane.

If you can record the noise that might help us a little.

 

Thanks gentlemen, as usual I get way more insight on this forum than anywhere else I ask.

I ran a bottle of Lucas injector cleaner that seems to have improved my mileage if nothing else. The temperature is much warmer again so I can't reproduce the noise atmo. One thing I noticed when I had the injectors off last time, there are small cones right at the tip of the injector which I assume keep it centered in the rail. Two or three of them are missing, probably because I got too rough with them during reinstallation. Can those cones be replaced?

No CEL, I'll have the coolant checked and have a block heater installed. I tried to put one in myself on a previous car, not something I care to try again.

I agree with RSPI that there may be sticky lifters. At my last oil change I did a much more agressive seafoam treatment, leaving it overnight and bringing the car up to temp again before changing the oil. That seemed to have improved things, but the valve train is still louder than it should be IMO.

In response to JPN, its just louder, not grinding or whining or anything else I can put a name to. I would say its an exhaust noise, but from inside the cabin it sounds like its coming from the engine bay.

 

If you are in that cold of a climate, I would consider using full synthetic.

 

could also have been your exhaust gasket, flange gasket etc at the front of the engine - they tend to swell up as they get warmer.

 

I have been running only Mobil 1 on my turbo vehicles since I was a wee lad.

This sounds like something I can check into, are you saying the gasket at the turbo when you say flange gasket?