6.5-T thermo stat's. . .

[M123KT-450]

Dose my 6.5 have to have the 195*F T-stat or could i go down to a 180*F or 160*F with out hurting it ?

Mikey

 

[NVW]

You can go down but mileage will suffer, unless you're in very high temps I would leave the 195's in.

Leo

 

[M123KT-450]

I did this with an EFI gasser once and yea the 160 was way to cold it ran to rich the 180 worked out awsome for the summer but by sept n oct the milage went from 13 highway to 9 highway so yea it dosen't take much for it start dumping fuel but that was a 5.8L MPI Ford . . .

But it sounds like the same effect will be had with the 6.5 as well. . .

Mikey

 

[TurboTahoe]

My understanding is that the 180 is the lowest temp you can get without causing problems. For the 95 you will need to ensure you get one of the blocking-type thermostats, as you have the earlier (and in my opinion better) thermostat type. I put a 180 in years ago, and it did pull a couple of MPG out of my economy.

If you have cooling problems, be sure to PULL the radiator and clean it out well with a garden hose and some 'scrubbing bubbles'. Don't assume that you have it clean just because it 'looks' clean.

I have a 95, and the only thing I would change is to put in the higher GPM pump. Other than that, I use distilled water and DexCool, and have never had problems.

-Rob

 

[JiFaire]

Single T-Stat system, make SURE you have a genuine ACDelco thermostat.

If you aren't, that is likely why you're overheating now.

Don't use anything else, I don't care WHAT they tell you. ACDelco only for single Tstat systms.

 

[bk95td]

Single T-Stat system, make SURE you have a genuine ACDelco thermostat.

If you aren't, that is likely why you're overheating now.

Don't use anything else, I don't care WHAT they tell you. ACDelco only for single Tstat systms.

x2 I've used napa and others and temps went all over the place. AC delco only.

 

[M123KT-450]

Easy now ! My truck is just fine ! Well temp wise, I was just wondering about getting it to run a little colder.

Mikey

 

[schiker]

Yep, 180F is as low as you should go. It takes 170F for the ECM to adjust from cold start "advance". Below 160F and it'll throw an OBD code (too cold for stable operation).

I run twin 180F robert shaw type. And some like the cooler underhood temps if you are in a warm climate to help with the electronics. 195F gives a little more performance.

 

[Dave01]

In my '97 what is the stock t-stat temp? On my gauge I run 185 steady, I assumed I had 185 stats. Are the stock ones 195?

The reason I ask is for running wvo the higher temp is a good thing, so I'm wondering if I'm running 10 degrees cooler than I could/should be.

 

[TurboTahoe]

In my '97 what is the stock t-stat temp? On my gauge I run 185 steady, I assumed I had 185 stats. Are the stock ones 195?

The reason I ask is for running wvo the higher temp is a good thing, so I'm wondering if I'm running 10 degrees cooler than I could/should be.

OK, I'm not totally sure, but I believe that the 97+ had two thermostats (Yes, I have a 99, but I haven't pulled the stats to check), one at 185 and one at 195. My understanding is that the 185 opens sooner, and provides cooling under light load, and if you are under heavy load, both of the themostats open up.

Experts feel free to correct me.

-Rob

 

[Matt Bachand]

OK, I'm not totally sure, but I believe that the 97+ had two thermostats (Yes, I have a 99, but I haven't pulled the stats to check), one at 185 and one at 195. My understanding is that the 185 opens sooner, and provides cooling under light load, and if you are under heavy load, both of the themostats open up.

Experts feel free to correct me.

-Rob

I'm no expert but I have the twin setup, and as far as i know most people change them in = pairs with matching T-stats.

I have heard talk about a mix but pretty sure most stick with - twins.

I run the 195's.

 

[SnowDrift]

x2 I've used napa and others and temps went all over the place. AC delco only.

x3

I have yet to find an application where OEM t-stat is not best

 

[M123KT-450]

Ummm. . . I do believe my truck only has 1 T-stat in it. . .or atleast the housing dose not appear to be a double unlesss the second is located else where. . .

I have always use "SUPER STAT" brand thermostats.

1. when they fail they fail wide open ! yes it runs way cold but it if failed shout it over heats.

2. Have never once had one fail.

3. uncle ran them for years in his tow trucks which lived 300-500K miles.

But cooling the 6.5 may no longer be an issue as it seem it about to get crushed. . .

mikey

 

[JiFaire]

3. uncle ran them for years in his tow trucks which lived 300-500K miles.

mikey

Let me guess, the tow trucks weren't 6.5 TD Diesels...

sigh. do what ever you want.

 

[M123KT-450]

Let me guess, the tow trucks weren't 6.5 TD Diesels...

sigh. do what ever you want.

Well you do have me there they where manly 350's but there was 2 400's 1 454 1 427 and 1 292. Trucks that weighted 9K lbs empty towing 2-10K LB vehicles . . . :thumbsup:. . .

But never fear the old 6.5-T fails again. . .stumbling bucking studdering turned into hard starting turned into not starting at all. . .:mad2: see nore under 6.5-T strikes again. . .:mad2:


Mikey

 

[JiFaire]

The only thermostat to put in a single T-stat 6.5 is the genuine ACDelco. I have seen guys try virtually every other type, and they all had overheating issues. The ACDelco also fails open.

However, if you want to keep applying gasser logic to your 6.5, go right ahead.. you may discover something that everybody else has missed. Then again, you may discover that we were right all along.

Either way, you will have discovered it, which seems to be the point.

As for the other issues, I'll continue that in the other thread.

 

[M123KT-450]

I have found the best cure all for the 6.5's. . .send the wreck to the CRUSHER !

Mikey