Thermostat Question

[Bill W]

Prices are all over the map, from $35 to $150. Also it seems many have different opinions on what temp for a thermostat. I can get a Mopar OEM 195 for around $50, but not sure if that is the way to go as many are using 180 degree.

[dave6666]

Gen 3 5037344AA. Boom. Done.

[Bill W]

Thank you, sir

[Fatboy 18]

So what temp does a Gen 3 stat open up at?

Next question, to drill or not to drill?

[Bill W]

Opens at 185 not sure about drilling. I think it also requires removal of intake manifold for installation

[Fatboy 18]

Yes you do, so a pair of new intake gaskets will likely be needed, you can then also clean up the engine valley

Warning, I disconnected the fuel line when I removed my intake manifold, there was a fair amount of fuel in the pipe, so make sure you are not smoking and you have rags and an extinguisher nearby!

Some people leave the manifold connected and just prop the front end up out of the way.

Worth hitting each bolt on the thermostat housing with a small punch prior to attempting to undo them, one of mine sheered off and I had to drill it out and try and get the last part of the bolt out with easyouts (and it was not easy)!
metal bolts and aluminium engine blocks cause Galvanic corrosion!
You will need a new gasket too.
Some pics here, and detailed info.
https://driveviper.com/forums/thread...ght=thermostat

[dave6666]

I drill (4) 1/8" holes in mine. Halfway up the sleeve on 90* increments around the sleeve.

As mentioned you can position the intake up out of the way without tampering with the fuel line if you choose not to. Pull the cowl and with blocks front and back you can do both the thermostat and the intake gaskets easily. The shorter blocks toward the windshield are not shown in the pics but you get the point. You won't need them to do the stat but to get the back end up high enough to get to the gaskets you will need them.

Pic08.jpg
Pic11.jpg
Pic07.jpg

[dave6666]

Opens at 185

I think I've stated it enough times that it has finally started to sink in around the Gen 2 Viper group. And that is...

1) Thermostats do not cool the engine. They are only a valve to allow correct warmup and correct minimum operating temperature. They can malfunction and cause overheating tho, but that has nothing to do with their temp set point. A broken 170* stat overheats the engine identically to how a broken 195* stat would.

2) If your car runs 200* in traffic with a 195* stat it will run 200* in traffic with a 180* stat. If changing from a 195* stat to a 180* stat cools your engine better, that's because the old 195* stat was on it's way out, not because the new 180* stat has 15* of bonus cooling built in lol. They do malfunction eventually. You will need a new one at some point.

3) Modern fuel injected engines need a certain engine temp to match the fuel maps. If you put in a 170* stat, and the very unlikely scenario that the car would actually run at that temp, you'd be below optimum engine temp for the tuning and could suffer performance loss. The engineers do get it right occasionally, and a Gen 3 185* stat is a good choice.

Below is a pic of a used 180* Caltherm stat that I bought from Big Brake Dave years ago (RIP). It for one, shows the holes to be drilled, and you can also see the wear marks from the valve action. The shiny polished metal ring at the top is where when it opens it slides up in to the thermostat housing. I believe on this one the issue with it was it was starting to slide crooked and bind. You can see it (not in the pic...) when you look around the perimeter that the wear marks are uneven. Indicating it's movement was no longer straight. When you get your old one out put it in a pot of water on the stove and heat it up. Watch it open to see if it still moves. That doesn't change the fact that it could still be operating crooked tho as the one I have opens, but runs crooked and binds.

20190817_060152.jpg

[Fatboy 18]

So the Idea of drilling the holes is just to help with burping the system, correct?

[dave6666]

It helps immensely with that.

[Fatboy 18]

It helps immensely with that.

Great, Got it.

[Viper Red]

It helps immensely with that.

Thank you for the useful info. Much appreciated.

[RyanLS.GEN2]

how many holes get drilled?

[Fatboy 18]

how many holes get drilled?

Read #7

[dave6666]

Read #7

Quite honestly whether a single 1/4" hole as someone else posted or the four 1/8" holes as I have done, the results are similar. The key is to get a place for the air to escape during initial filling. Just don't get them too high on the sleeve or they won't be effective.

[MH60M]

Drilling the 4ea 1/8" holes and installing my thermostat this week.…..I'll just copy the pic unless there is a better placement......Dave?

Thanks

[GTS Dean]

Too many holes, or too much open area will not let the engine warm to full operating temperature in cool weather. This will not allow proper heater function, nor will it let the oil temp get hot enough to boil off water condensate in the crank case.

[Bill W]

Yes you do, so a pair of new intake gaskets will likely be needed, you can then also clean up the engine valley

Warning, I disconnected the fuel line when I removed my intake manifold, there was a fair amount of fuel in the pipe, so make sure you are not smoking and you have rags and an extinguisher nearby!

Some people leave the manifold connected and just prop the front end up out of the way.

Worth hitting each bolt on the thermostat housing with a small punch prior to attempting to undo them, one of mine sheered off and I had to drill it out and try and get the last part of the bolt out with easyouts (and it was not easy)!
metal bolts and aluminium engine blocks cause Galvanic corrosion!
You will need a new gasket too.
Some pics here, and detailed info.
https://driveviper.com/forums/thread...ght=thermostat

So, provided you don't have the nightmare scenario depicted (Wow! What a time you had!), how long does it take to change the thermostat? Looks like several hours anyway. Will probably replace heater hoses as well.

[Fatboy 18]

A day will cover it, providing all goes well

[Ross L]

First time gen 1. Several hours. 2nd time, maybe 1-2 hours. I didn't remove/loosen the intake, just the winshoeld cowl and the rear driverside raditor hose. Think I pulled the crossover and thermostat as one piece. Good luck!

[MH60M]

Changed thermostat and broke new intake gaskets during intake manifold install..... Sadface

[Fatboy 18]

Sucks

[dave6666]

Changed thermostat and broke new intake gaskets during intake manifold install..... Sadface

How does one break an intake gasket?

[Fatboy 18]

Easy done, if you catch the edge of the inlet manifold on the Cylinder head or loose your grip on the manifold due to awkward angle or those small white plastic tabs displace on the end of the gaskets making them slip down.

Just saying

[Viper Red]

OEM Gen1 stats are 190 I think.
I replaced mine with a 200 one.

I feel it runs better in my climate.
Just need that coolant to stay in the radiator slightly longer.