Best engine temp
 

So what is the best engine temperature. I know most cars run at around 1/2 on the temp gauge. Under 1/2 is too cold (oil is to thick = lower mpg). Is 3/4 ok? I know being in the red (usually around 7/8) is bad and can harm the engine.

Quote:So what is the best
 

I heard somewhere that the additives in oil don't really reach their full effectiveness until the oil reaches somewhere around 200 degrees.

Car Guages Inaccurate
 

I think that the hotter the engine, the more efficient it becomes (I just put a hotter thermostat in, so I hope it does). The hottest I could find was 192F which replaced the 170F stock version. But here's the kicker...

Most vehicle guages don't really display the "true value" of the engine's temperature -- I'd recommend a ScanGuage tool or datalogger to confirm the coolant temp output. The car's guage usually moves up to the "normal" position and won't move if the temp goes up 25 degrees, for example. It keeps the general public from watching the guage too closely and freaking out if it moves too much.

There has to be a "sweet spot" for engine temp. The hotter the better, but too hot and you get pre-ignition/pinging, risk of cracking the block, etc. Prolonged exposure to 7/8 of the "red zone" will wear out parts sooner and break-down oil sooner.


RH77

Because of driving
 

Because of driving conditions (long drive uphill) i changed my thermostat on my truck from 195 to 180. I did this to prevent overheating (wich seemed to be hurting my power going uphill).

I recorded no difference in mileage. (although my rig is a '91 and TBI, hmmm)

I've actually done a number of different tests and noticed almost no difference in mileage, (i'm always between 20-22mpg's.

I think rh77's recent luck
 

I think rh77's recent luck with the 192 thermostat suggests that hotter is better, and I see no problem with it being this hot, or else they would not have built a thermostat for this temperature.

Quote:I think rh77's recent
 

Here is another option too. It's kind of pricey but may be worth the benefits.

https://www.evanscooling.com/main1.htm

There's a guy on one of the Yahoo groups that is running this in one of his vehicles and he was able to find a 205 degree thermostat so he could take advantage of the special coolant. He did have to do some mods to his fan sensor so he could fool it into waiting until the temp got higher before it kicks on. I may look into this the next time I need to flush my system.

fyi, the stock tstat in my
 

fyi, the stock tstat in my metro is a 192.

and i know i've mentioned this in another thread, but consider running at least a partial grille block too: for quicker warm-up (not just the engine - the transaxle of a fwd car will run warmer too with reduced airflow into the engine compartment) and improved aerodynamics.

95% of my grille has been taped over since november. temps have been fine.

I had a radiator block on
 

I had a radiator block on for a while, but it seemed to make the engine run colder, I think I'll try out a grill block though, can't hurt.

I'm actually considering
 

I'm actually considering getting a smaller radiator as well. The 5th generation civics all had smaller radiators than the 4th generation civics (which I currently have). Since I am swapping in a motor from a 5th generation civic I could actually be doing more harm than good with my original radiator.

Quote:I'm actually
 

Indeed, it is often said on honda-tech that efs (88-91 civics) had monstrously large radiators. Seems like a good and permanent solution. How much does on cost out of the junkyard?

Re: Quote:I'm actually
 

I think they are usually something like $20 max. I should look tomorrow. The problem is that I have only seen a few 92-95 radiators and I'm unsure if other cars' radiators are compatible or not.

Well, you're sticking in a
 

Well, you're sticking in a 92-95 engine, why not radiator? I'm pretty sure they work. Good luck with the half price sale!

192-Temp
 

I haven't had a bit of trouble with the 192-stat, in fact it really helped my mileage. I've run up hills, done full-throttle runs, idled in heavy traffic -- no problems whatsoever. Although...

I'd like to get some sort of baffle to keep air from moving over the radiator to get the temp up quicker in the cold weather -- I do a lot of Interstate/high-speed driving, so sometimes it takes a while to heat up. Cardboard is the easiest choice, but cheesy; plexiglas would look good but is expensive, harder to cut and could melt. I'm thinking of sheetmetal or a bra or something. I see big rigs and school busses with these padded-looking covers over the grill, so something like that or slip trim some sheetmetal and slip it in there.

I'm definitely sold on the hotter temps = better mileage theory.

RH77

I say do plexiglass over the
 

I say do plexiglass over the back of the holes in the front of the car, not up against the radiator, same effect, no melting.

Does a hotter thermostat really help?
 

that guy who is runing a 205F engine sounds like he is useing Propylene Glycol, a heat transfer fluid that I've used in solor hot water systems for in floor heat, it's nice stuff, slightly different propertys then etholyne glycol (the coolent you have now) he's claming to be useing a "water free" mix, not sure what's in that, but I know that the pure stuff we get 5 gallong buckts full of is so slipery that a pump can't pump it untill you ad some water, I used to have charts of how it was affected by heat, and how well it transfered heat, and Propylene Glycol seems like a good choice, not overtly better, other then it will not kill you if you or a pet drinks it, it's kind of sweet and a little bitter, they put it in ice cream, and cookies, and all kinds of foods.

my civic vx came stock with a 180F thermostat, a 192 is avalible, but wouldn't the car have been designed with the 192 if it was a good idea for mileage? it's a higher compresion engine, with lean burn so it's going to run hot at times i would think.
so why should I switch to a hotter thermostat? how much of a differnce will it make?

also, as far as smaller radiators, Geo's, civic 1.3, HF, VX, HX, all have half size radiators, from what I hear from people who race useing them, if they are kept clean there is no problem cooling under high loads, the half sized radiator is something like 14" wide, and 15" tall, the guy at NAPA was confused as to what would take such a small radiator.

Quote:my civic vx came stock
 

I think the Insight uses a 195. It's a mix between performance and FE.

Meh, doesn't run too hot. 3% difference.

my car came with a 195
 

my car came with a 195 thermostat but the problem was when I was driving around city my fans would turn on most of the time. I was told to buy a 1.2 bar radiator cap because it allowed the temps to be higher without overheating, or something like that.

After I bought the 1.2 bar cap my fans rarely turn on. They either turn on when I've been driving too long in traffic or when I'm racing for a prolonged period of time.

I noticed that my dad has a 1.1 bar radiator cap on his new accord and his fans rarely turn on too. Before the 1.2 cap I had a 0.9 cap which came with the car stock.

cap
 

The radiator cap only controls the pressure in the cooling system - the higher the pressure the higher the boiling point of the coolant will be - unless you vent coolant it should not affect the fan turn on temp. There is a temp sensor in the radiator for turning on the fans - thermal switch. They could also be controlled by the computer but usually by the radiator so they will run when the engine is off if the radiator is hot enough. xB is running at 182-188 degrees - not hot enough to get the idle down to the desired 650rpm range ends up at 850 all the time wasting gas. Will have to tweek the stat opening temp and check the seals on the valve.