Normal Operating Temp for a Merc 170

[rndcomp]

Can someone out there please validate that the normal operating temp (at idle) for an 87 Merc 170 is around 170 degrees. I am pretty sure that I read this somewhere. Also, and I apologize the dumb question, if I were to remove the pressure cap off the FWC reservoir, should I expect to see the coolant leave the reservoir around 170 degrees (or whatever the t-stat is set to) to indicate that the t-stat has opened and is passing water?

Thanks!

 

[andy1canada]

Re: Normal Operating Temp for a Merc 170

Howdy,

I think 170 is okay. You can have your engine operating temp checked and verified by a heat sensing gun if you're not confident with your current gauge reading.

Rather than risk a face-full of hot coolant, just check that you have a good flow of coolant coming out of the drive unit while it's running on a garden hose. Also, if you haven't changed your impellar in the water pump or don't know the last time it was done, you need to do that as well.

Good luck,
Terry

 

[fourwinnsdook]

Re: Normal Operating Temp for a Merc 170

Mine runs at about 16o or below, but i don't have the FWC. i've heard that the FWC runs a little hotter, so that sounds about right, Don't remove the cap. That's dangerous. use a heat gun.

 

[rndcomp]

Re: Normal Operating Temp for a Merc 170

Where specifically on the out drive should I look for coolant? I want to make sure that I don't mistake the excess water coming out of the muffs for raw water coolant. Also, do I really want to see "coolant" as in fresh water coolant leaving the drive, or should I only see the raw water coolant?

Thanks so much for all of the great advice!!

 

[fourwinnsdook]

Re: Normal Operating Temp for a Merc 170

The water on mine comes out under the outdrive between the two trim cylinders. I don't know how much will come out but you will not have any coolant comming out, only what circulates through your lower unit. everything comming out will be from your muffs.