160 deg. thermostat

[Bub]

My 1998 Z28 will soon have a 160 degree thermostat installed. The question is, under normal driving will the oil get hot enough to burn off the contaminats that get in the oil following the first few minutes after startup? FYI: I'm using the long K&N oil filter and (flame suit on ) Mobil 1 15W50.
Bub

 

[Patman]

In the hot summer, yes. I ran a homemade 160 thermo in my 98 Formula and found it still ran normal coolant temps in the hot summer, around 190-200F. But once it got below 50-60F, my coolant temp rarely went above 170F, not good. All these numbers were verified with autotap.

So for Texas in summer, the 160 thermo will be fine, but if you drive it in cooler weather, switch back to stock. It's an easy swap, even I could do it myself and I'm not very mechanically inclined.

 

[ShootingStar]

My dad switched thermostat's twice a year, winter and summer as far back as I can remember, as a part of regular maintenance,. Never a problem.

 

[ShootingStar]

quote:

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Originally posted by Bub:
FYI: I'm using the long K&N oil filter and (flame suit on ) Mobil 1 15W50.
Bub

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Bub, No one on this board will flame you for using Mobil 1 or just about anything else. (Well... Maybe Fram filters.

) You've just been hangin out in those OTHER forums too much!

 

[Patman]

quote:

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Originally posted by ShootingStar:

quote:

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Originally posted by Bub:
FYI: I'm using the long K&N oil filter and (flame suit on ) Mobil 1 15W50.
Bub

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Bub, No one on this board will flame you for using Mobil 1 or just about anything else. (Well... Maybe Fram filters.

) You've just been hangin out in those OTHER forums too much!

---

I don't think he's worried about us bugging him about using Mobil 1, it's the thicker 15w50. I would like to see some oil analysis results on that 15w50 in an LS1 though. I bet the numbers won't be as good as the other reports we've seen here. 15w50 is too thick for the LS1.

 

[Ray H]

It seems to me the only way an engine would run cooler with a 160 degree thermostat depends totally on the ambient temperature. In warm climates the 160 degree piece would open sooner than the OEM piece, but that doesn't mean the engine would be restricted to 160 degree operation in operation. My understanding of the 180 and 195 degree OEM thermostats was to insure that the engines run as warm for emmissions efficiency as possible, to get them to that minimum temperature as soon as possible, and are intended for year 'round operation. Take any vehicle out on the I-15 freeway from San Bernardino to Las Vegas in the middle of August, and the engine's going to run as hot as it's gonna run regardless what opening temperature thermostat is installed (or even whether a thermostat's installed). The only variable in that scenario is how soon the engine will fully warm up.

 

[Malibu]

Ray H, it depends on the cooling capacity of the radiator and how much reserve cooling capacity is built into the cooling system by the manufacturer.

On my '82 Pontiac 6000, the temp gauge stayed considerably lower on the temp gauge dial when I put a 180 stat in place of the factory original 195. And that was true in 105 degree summer weather as well as more moderate weather.

Now a radiator that's partly clogged due to scale and sludge buildup will not have much, if any reserve capacity and the vehicle could run as hot with a 160 as it does with a 195 in warm summer weather.

Car makers have used 180 stats since the 1950's - long before there were any emmission regulations in place.

 

[Whimsey]

I would think that if you change the temp at what the vehicle was intended to run at you can cause all sorts of unintended problems. Like running in the cold cycle mode for the fuel injection. This could cause worse fuel economy and even more damaging is earlier failure of the cats by causing too rich of a mixture and that it can also dilute your oil with fuel. For better or worse today's vehicles are not that "friendly" when it comes to changing the parameters set by your car's computer. But then again, when it comes to computers I have a difficult time even turning the d**n thing on!

Whimsey

 

[Malibu]

Bub, RV shop owner mechanics have been installing 180 degree thermostats in place of the factory original 195 degree stats for years to help the hard working motorhome gas engines run cooler and alleviate pinging. But no one runs a 160 as it is too drastic a temperature drop from stock. Like Patman said, however, its possible you could use the 160 in the heat of summer. Check your spark plugs a month after putting in the 160 stat to see if they are accumulating carbon. If so, move up to a 180. Also check your gas mileage. Even the 180 will result is a bit of a loss in fuel economy - about 1/2 of 1 MPG.

 

[Patman]

In the LS1 f-bodies, it won't stay in cold loop because it has to be under about 140F to be there. It's not possible no matter what thermo you run in there.

My gas mileage did not suffer in the summer with the colder thermo, but it sure did in the colder weather.

[ February 23, 2003, 12:50 PM: Message edited by: Patman ]

 

[Shannow]

Not sure on the systems that your cars have, but if going cooler, I'd only do it on an engine that had a two piece thermostat that controlled both the inlet AND the outlet temperature. That way, there's no chance of a cold spot on the front pots.

A while ago I had a thermostat housing made that controlled the coolant inlet temperature. Found that after installing it, the idle speed on carbed 4s and V-8s increased by a couple hundred RPM for a month after installing it. Mileage went up.

A guy down south made them for a while, and was getting great results with them balancing engine temps. 20 plus MPG on 300 horse 350 chevs on propane. (I ended up buying one of his kits, and was most impressed).

Big thing to check was the pump flow at idle, as some pumps can't circulate at 600RPM, leading the motor to get hot and ping as you leave the lights.

 

[Soma07]

IMO it'll be fine.

Sorry, but I dont buy the "It'll make it run rich" theory (if you can even call it that). Why? Closed loop operation

The computer is going to maintain 14.7:1 as long as the coolant gets warm enough for it to enter closed loop (which it will) and the O2 sensors are reading accurately.

In theory the cooler stat will decrease fuel efficiency (due to decrease in thermal effeciency)but I haven't seen any hard data that says even roughly how much.

Also FWIW my last oil anaylsis was run with a 160 stat and it showed no water or fuel present after 5300 miles (despite my car running open loop 24/7).

 

[Patman]

FWIW, the stock thermostat in an LS1 is a 177-184F unit. At least it was in my 98, the owner's manual said so, and my observations on it's running temp with Autotap confirmed it (since it would run about 190F on the highway on a 70F day)

The stock thermo in my LT1 is a 180F unit.

 

[Bub]

on my Z28 a-tap has confirmed that the coolant temp stays more around the 210-220 deg far. As for running in open loop, all has been taken care of by LS1 edit. The flame suit was referring to the weight of the motor oil, not the manufacurer.
Bub

[ February 24, 2003, 01:23 PM: Message edited by: Bub ]

 

[Patman]

quote:

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Originally posted by Bub:
on my Z28 a-tap has confirmed that the coolant temp stays more around the 210-220 deg far. As for running in open loop, all has been taken care of by LS1 edit. The flame suit was referring to the weight of the motor oil, not the manufacurer.
Bub

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Do you have any plans on getting an oil analysis done? I'm dying to see how a 15w50 Mobil 1 report in an LS1 would look.

 

[Bub]

Yes I plan to. But I'm still waiting on a 12 bolt rear to be installed. I don't plan to see great numbers on TBN ox. ni. ect. because of a slight blowby on the no. 1 cylinder, but I'm doing it maily for the wear #s This car has had impecable maintenace since I bought it, but It has had the hell driven out of it. Should make for an interesting analysis.
Bub

 

[outrun]

Bub,

In short do not chnage to a 160 F thermostat in an LS1.

This has perhaps been the silliest of the F-Body bolt-on controversies.

A)If you truly seek cooling capacity increase of your system for hot Texas summers consider (although more expensive)

-A Be Cool Aluminum HP radiator (600.00$ from Jegs High Performance Radiator)

-Lingenfelter Aluminum Radiator

-Mezzier LS1 35GPM Electric Water Pump

-Upgrade your fans to high torque Tahoe/Escalade units (might require some wiring and harness fabrication)

On the Thermostat issue, in summer your engine will run hot yes, but it can also run at the 160 F level resulting in a loss of the optimum temperature GM engineers intended.

Including:

A)Improper OE oil temperature...and from this board synthetic or dino regardless the lubricant will perform at the a certain temp range (ie 180 F +) Why loose the cleaning properties at low temp?

B)The same will hold true for the ATF assuming your car has the 4L60E hydromatic. If the coolant is 160 F the ATF will hover and equalize around that temperature; again a no-no.

C)Finally, Lingenfelter Performace Engineering had an article 2years ago essentially shooting down the proliferation of the aftermarket 160 thermostats on LS1 engines.

The thesis of the argument came down the thier findings that GM engineers had fined tuned the LS1 very delicately.

Taking into consideration the quick cooling thermodynamics and heat capacitance of the new Aluminum alloy engine, timing, intake air charge temperature etc the conclusion was the LS1 performed at optimum at 177.8 F

Hence the 180 F Thermostat was most logical Bub-

Your LS1 may run hot in the miserable summer, the only issue is that you should be worried about is if the high engine temp is being caused by a faulty OE component. At that point unless your in some Super Street racing category would be to replace it with an OEM or equiv part. The LS1 is wonderfully designed in stock form and even on the hottest days on bone stock engines (including thermostats) my friends have consistently runs low to mid 12's.

Not to shabby for a 180 F Thermostat

Think this was on out Man. I almost switched to the 160..then i came to my senses.

 

[Bub]

Well sorry to say it's already been ordered. If it turns out to be bunk I'll ditch it and order the 180. Thanks for the advice.

One thing that I forgot to mention is that the fans will be set at 175 (small) and 190 (large) so the engine will acutally be running hotter than the t-stat opening point. I selected the 160 because I plan to later install an electric water pump and rig the pump and the fans to run at the flip of a switch. The 160 will allow the engine to cool down more before the t-stat closes.
Bub

[ February 24, 2003, 10:53 PM: Message edited by: Bub ]

 

[TheTanSedan]

Hotter you can run it, the better. Only limitation is that most coolants can't control the temps without boiling.

Even Smokey Yunick said engine temps ought to be high for oil to work the best.

Hot = ring seal = engine longevity = power production = emissions reduction = fuel economy.

Associated "problems" need their own solution.

 

[outrun]

Bub,

Better yet keep the 160 thermostat as a spare but don't install it.

However the hand switch pump and cooling fan may be better.

if the engine zooms to 200 or more simply turn on your accessories to bring it back to 180

LoL sorry about my adamancy about the 160F. i just hate to see another F-Body owner fall into a blind bolt on trap.

GM did an amazing job on that LS1, hate to see you diminish its performance.

As the previous guy said. HOT is actually good