Getting Colder: Coolant Low and Revs High
10-21-2014, 08:00 AM
#1
Junior Member
Thread Starter
Getting Colder: Coolant Low and Revs High
Nights are starting to get colder in my parts, and I've noticed that the truck will do two things I hadn't noticed in the summer (this truck is new to us, so this is our first winter with her):
First, on a cold start the "Top Up Coolant" warning comes on, but will then go away once the engine warms up. My guess is that its probably a little low (which is why the sensor is tripping) but as the coolant warms up and expands, it meets the minimum threshold. I did some searching and found out that I need to either Zerex or head to the dealer for some fluid. I haven't checked the level yet (since the warning isn't constant and doesn't appear on a warm start). Anything else I should note before I top it off?
Second, the engine will idle about 200rpm higher than usual. During the summer, the engine idles around 600rpm, but I noticed that on a cold start, it will idle at 800rpm until (I assume) the engine warms up, when the idle drops back down to 600rpm. My thought was this was designed to get the engine up to temp faster, but anything I should be worried about?
First, on a cold start the "Top Up Coolant" warning comes on, but will then go away once the engine warms up. My guess is that its probably a little low (which is why the sensor is tripping) but as the coolant warms up and expands, it meets the minimum threshold. I did some searching and found out that I need to either Zerex or head to the dealer for some fluid. I haven't checked the level yet (since the warning isn't constant and doesn't appear on a warm start). Anything else I should note before I top it off?
Second, the engine will idle about 200rpm higher than usual. During the summer, the engine idles around 600rpm, but I noticed that on a cold start, it will idle at 800rpm until (I assume) the engine warms up, when the idle drops back down to 600rpm. My thought was this was designed to get the engine up to temp faster, but anything I should be worried about?
10-21-2014, 10:55 AM
#2
Out Of Control!!
Yes, top up coolant.
Use MB coolant, as mixing bands/formulations is no big deal on engines where the fluid is changed regularly (I.E. every 2 years or so) but long life fluids should not be mixed.
The warm up should be good as long at a it drops when the engine is warm (and no codes are showing)
Check how long it takes driving to get up to 180 (Maybe a bad thermostat)
Use MB coolant, as mixing bands/formulations is no big deal on engines where the fluid is changed regularly (I.E. every 2 years or so) but long life fluids should not be mixed.
The warm up should be good as long at a it drops when the engine is warm (and no codes are showing)
Check how long it takes driving to get up to 180 (Maybe a bad thermostat)
10-21-2014, 10:59 AM
#3
both are normal.
your truck is low on coolant. they are all low all the time. there is either a small leak or just the phase of the moon. as long as you dont need to add monthly dont sweat it. add enough to cover the vertical brace visible through the opening on the expansion tank with the cap off and cold engine.
the higher rpms are also normal. this is so your heat starts working sooner and to achieve faster light off of the cats. turn off heating and watch the rpms drop if you desire so.
your truck is low on coolant. they are all low all the time. there is either a small leak or just the phase of the moon. as long as you dont need to add monthly dont sweat it. add enough to cover the vertical brace visible through the opening on the expansion tank with the cap off and cold engine.
the higher rpms are also normal. this is so your heat starts working sooner and to achieve faster light off of the cats. turn off heating and watch the rpms drop if you desire so.
