Coolant cold, Oil warm: Is this a good thing?: Grassroots Motorsports forum: Grassroots Motorsports Magazine

Subscribe get a full year for only $23.95 Sample Free Test Drive—no strings attached

Oct. 20, 2011 5:49 p.m. neckromacr Reader

Anyone who's had a 16v Scirocco, you know they run a little hot under the collar in stock form. "Normal" is just over the midway mark. (Not sure if GTI/GLI have the same characteristic)

Well after some renovations under the hood ditching AC and PS while trading V-belts for Serpentine I'm noticing the coolant temps are running a little on the cool side but oil temps are right at normal.

I know the general rule is if you had to run too warm or too cool, you should go a bit too warm. But I always thought this was to ensure the oil is also getting up to running temps. Since the oil is reaching proper temp, should I be worried about the coolant running a bit too cool?
Oct. 20, 2011 5:54 p.m. belteshazzar SuperDork

none of the moving parts touch coolant, so no.
Oct. 20, 2011 6:00 p.m. Taiden Dork

throw a tstat at it! they are pretty cheap, aren't they?
Oct. 20, 2011 7:20 p.m. neckromacr Reader

belteshazzar wrote:

none of the moving parts touch coolant, so no.

Thanks, I was thinking so, just wanted to make sure it wasn't something I was missing.

T-stat is new but OE normal temp. The low temp indication is just under the mark instead of just over it, and the fact that the ambient temp are falling with the season hasn't eluded me. If the temps continue to drop with the colder seasons I may run a colder t-stat, my only concern would be it raising the oil temps.

The sheer size of the AC condenser I pulled out from this car makes sense of why the coolant temps dropped. When I took it to my shop to dispose of it they thought it came out of a full sized truck, not a '80's compact.
Oct. 20, 2011 7:42 p.m. Taiden Dork

The radiator may cool more efficiently without AC system junk, but a properly functioning tstat should keep any super chilly cooling system in check.

Where is the coolant temp gauge sender located? Is it far from the temp sender that the ECU uses? Is it near the radiator, outside of the tstat circuit?

Stock temp gauges usually have three settings

COLD
WARM
WARPED HEADS

Might be worth getting an external temp gauge if you're worried about your coolant temp.
Oct. 20, 2011 7:56 p.m. neckromacr Reader

I know the external gauges would be more accurate, it just seemed odd that the OE stuff suddenly changed its behavior.

The coolant sensors all live in the side of the head. Oil sensors live on the oil cooler. Although it might be worth doing a good ground cleanup, the oil sender is known to give a higher reading if the grounds haven't been cleaned in awhile.

It's a VW, first step in trouble shooting anything seems to be clean grounds.
Oct. 20, 2011 8:54 p.m. fasted58 SuperDork

canoe
Oct. 20, 2011 9:46 p.m. neckromacr Reader

fasted58 wrote:

canoe

Excuse me? This is indeed a perfectly legitimate thread just trying to get some information. I fail to see what product I'm supposedly trying to push.
Oct. 20, 2011 10:11 p.m. novaderrik Dork

cool water= less preignition tendencies, which means more leanness in the fuel mixture and/or more timing, which then = moar power.

hot oil=less friction, which then= moar power..

so to summarize:

cool water= moar power

hot oil=moar power

cool water+hot oil= way much moar power.

in theory, anyways..
Oct. 20, 2011 10:32 p.m. fasted58 SuperDork

neckromacr wrote:

fasted58 wrote:

canoe

Excuse me? This is indeed a perfectly legitimate thread just trying to get some information. I fail to see what product I'm supposedly trying to push.

Unless you also post nfl jersey, shoe and handbag canoes under another name this was obviously not directed at you

I tagged about 20 canoes last hour by some foreign paddler, they have since been removed by staff

There has to be a better way.. maybe as discussed in the canoe thread today
Oct. 20, 2011 10:40 p.m. Marjorie Suddard General Manager

I removed the canoes. Then I went back around and tried to remove all of the "canoe" tags. Missed this one, sorry.

We appreciate y'all helping to look after things here, but as Tom has pointed out a few times before, we don't actually search on "canoe" anymore. The tags and images can be amusing and sometimes a single one helps us spot a spammer, but as soon as we see them we go after all their posts anyway. More than that is overkill and wastes valuable time you guys could be spending discussing more fun stuff.

Thanks, Margie
Oct. 20, 2011 10:46 p.m. fasted58 SuperDork

In reply to Marjorie Suddard:

I usually hit the " ! " and tag "canoe" until they go away, maybe I'm just old fashioned like that.
Oct. 20, 2011 11:04 p.m. neckromacr Reader

fasted58 wrote:

neckromacr wrote:

fasted58 wrote:

canoe

Excuse me? This is indeed a perfectly legitimate thread just trying to get some information. I fail to see what product I'm supposedly trying to push.

Unless you also post nfl jersey, shoe and handbag canoes under another name this was obviously not directed at you

I tagged about 20 canoes last hour by some foreign paddler, they have since been removed by staff

There has to be a better way.. maybe as discussed in the canoe thread today

Ah, my apologies, I see what happened. Sorry for getting so defensive, I haven't see the canoes replying just when the make new threads.
Oct. 20, 2011 11:50 p.m. SlickDizzy SuperDork

Have you tried a new gauge temp sender? My girlfriend's Jetta "ran slightly hot" until I spent $12 on a new sender. Now it is smack in the middle of the gauge. YMMV, it is a VW after all.
Oct. 21, 2011 8:32 a.m. Marjorie Suddard General Manager

Fasted,

NBD--although the "canoe" tag is actually kind of a PITA, it's also pretty amusing (esp. when hotlinks are employed). The ! thing, OTOH, does really help, and I do appreciate how long it took you to track down that handbag-pusher. He was prolific!

Margie
Oct. 21, 2011 8:52 a.m. iceracer SuperDork

Back to the subject at hand, define "Cool". Cool can be OK. Cold is not. Seems to me you are trying to build a mountain out of a mole hill.
Oct. 21, 2011 9:05 a.m. neckromacr Reader

not mine, but hotlinked for GRM compliance.

16V "normal" was always just above the warning LED in the middle of the gauge. I'm running just below it now.

And yes, I see in the title I used the term "cold" when it should have indeed been "cool"
Oct. 21, 2011 10:55 a.m. porksboy SuperDork

SOP for German cars is an overly comex Technical Service Bullitin to repair a simple problem. Often employing spending lave sums of cash on an updated part that has no apparent differences to the part it replaces. Usually an ECU is involved. The end result being no noticeable difference in performance, driving characteristics, or resolution of the original problem.

Often the ultimate resolution involves the cleaning of ground wires or resoldering cold solder joints in plug connections.