I was told to replace the engine thermostat with a 160 instead of 190 when gets warm out by someone who has worked on hundreds of step vans just like mine, with 6.2 and 6.5 n/a engines. He was buying fleets of them from the post office, fixing them up and selling one; and i just happened to get one with a newer engine and i don't want to ruin it.
Anyway, so he says it will shorten the life of the engine if you keep the 190 in due to excessive heat.
The problem is that i have an svo system in mine with several heat exchangers that use coolant that comes directly from the head, and i am not looking forward to a 30 degree loss in heat for them. But if that's the way it goes then i will just have to deal.
Can anyone shed some light on this issue? Is this a standard practice with these engines? If you put a 160 in place does that mean the coolant coming from the head will never be any hotter than 160 F?
thanks,
Paul

Don't use a 160 thermostat in a 6.2!!!!! The lowest thermostat to use should be a 180. If the engine isn't cooling properly, get a calibrated fan clutch from Kennedy. :eek:

Is it possible you could explain that a little more? First of all i am almost certain it is a 6.5 n/a, but i don't know if that makes a difference here. I just call it a 6.2 because that's what the van originally had and all the components are compatible with the 6.2.
What is the reason for not using a 160 in this engine? Not that i want to use one, but i think the one that was in it when i bought it was close that, maybe 165. But i replaced it when it seemed like the engine was running too cool.:cool2:
thanks,
Paul

Greasefire, Camilleri is right, do not use a 160 degree stat in the 6.2/6.5. At least 180 degrees is needed to boil off the water that the engine acculmates in the crankcase due to condension. Year round I use 195 stat in my 89 van with a 6.2. Used the same stat in my 84 6.2 van for 237K. And that engine is still a great engine today. It is sitting in my shop doing nothing right now but I would use it in a heartbeat if something happened to my newer 6.2. If you have a good radiator, a good fan and fan clutch, and your engine is not all scaled up in the water jacket, it will cool fine. I'm sure a 180 is fine, but I wouldn't want my engines to run any cooler. My engine runs at 195 all the time regardless of ambent tempature. But I don't tow heavy loads very far or over 55/60 MPH. The 6.2 is not a big horse. I like them because they are great for fuel milage and will live a long time, if properly cared for. I also like my 6.2 because I love the smell of french fries coming from my tail pipe in the morning!):h Mike

The reason for not running a too cold thermostat like a 160 is it also causes increased cylinder wear. Engines run best and longest between 180 and 200 degrees. Important thing to note is to run the propper type of thermostat, Robert Shaw or OEM only! These are high flow stats and other types of stats can't flow enough coolant for propper opperation. In the early 80's J engines came factory with 180 stats and C engines came with 195's. If you live in cold country where a hot heater is of importance, run a 195. Also on older engines, a 195 helps the pistons to expand a little extra to take up the wear in the bore.:cool:

Where can you get those brands of thermostats? I called both Napa and Autozone and they don't have those kinds, and they could not tell if the ones they did carry are high flow or not.
They did say they have one that is listed as "original equipment" which should be the same as what was put in when it was manufactured - would that work?
thanks,
Paul

I think DC meant Robershaw thermostats, but in the extra or extreme duty type. The AC Delco and the Robertshaw Stats look the same, and perform the same. I'd install a RS 180 stat in your 6.2 and forget about cooling, because you won't have to worry with it. You can get the Stat you need at KennedyDiesel.com

I'm also aware that another chain carries them boxed under another name, maybe someone will chime in about that.

chevydiesel, thanks, that's what I meant. Maybe I need to get some grecian formula for my gray hairs and loss of memory. :D

Discount/Advanced auto parts is where I buy Robertshaw T-Stats. I look for the Race or extreme duty. They will flow water even if stuck. Motor oil does not provide the protection you seek until it reaches 180 so the guys here are very right. I like (as often as possible) to let my 6.2 run several minutes before touching the GO pedal. with the High flow t-stat you would let it run a little more. I like to see my temp. gauge come up from cold a little before running the old girl. Don't think I always do this. I just like to as often as possible but always let her run a while in winter conditions. brent

Any of the thermostats (160, 170, 180, or 195 degree) will let your engine run warmer in warm weather if you are going up a long incline (mountain pass). Cold weather demands a 195 thermostat if you want warm air out of your heater. The higher temp. will also help the oil disperse from the crank to the the cylinder walls.

Get the thermostat with the biggest diameter hole. Some have very small holes which means low coolant flow!!! The standard Delco has the big hole.

while i was out the other day i stopped at every auto place i passed and none of them had any thermostats for a 6.2 at all, let alone a high flow; and kennedydiesel.com is out of them and the dude on the phone was not very friendly or helpful, he just said he was out too bad shut up, etc.
So what happens if i just go to autozone and get whatever 180 they have? They actually do have two different types of them including one that is the same that originally came with the engine. They coudn't say if they were high flow or not. Do you risk damaging your engine by walking in and taking what they have? I do have a temp gauge on the dash so i could easily tell if it is over heating but i am not sure if there is more to it than that.
Has anyone else got one at autozone before? That's where i got the 195 i use for winter and it does not seem to cause any problems - but then again i don't know enough about all this to say for sure.
Paul

If you know what you are looking at it is easy to tell the difference between the high flow type and the others. The factory and RobertShaw stats have a cage on the bottom of the stat. It has about 3 rectangular shaped holes that the coolant flows through. This is a much different design than other stats. You could always try your local gm dealer and ask for a stat for a 6.5, because the dimensions are the same. I will try to post a picture of a stat for you when I get home.:rolleyes: