Coolant temp

[RustyCaddy]

i can't seem to find this anywhere but what is a ballpark running temperature for coolant on a 1.6 NA?

put a digital gauge in a rebuild for breaking it in and the coolant temp at the outlet of the head to the water pump is running between 200 and 210 F mostly (sometimes up to 217 F running the rpms high going uphill to seat the rings).  No sign of air in the coolant return line to the reservoir so far.

the gauge might be reading high; it was used.  should i be worried?

would like to take it the 50 miles to work and back tomorrow and the wife would like to have her car back (for good!)

any advice appreciated

Thanks

[maxfax]

What temp thermostat you running???  I have a temp gauge taking it's reading in the same location..  

With a 195F stat it normally ran between 200 - 210 with spikes a tad below 220 on a long hard pull...  The temp never quite got to 220F and always dropped promptly upon descending the mountain..

I now have a 185F t-stat and it typically runs about 190 - 200 ish at the outlet and will spike to 210 on the hills...

The factory gauge was maybe just at the halfway point at 220ish

[RustyCaddy]

Max,

i think it is probably a 185 F stat but i can't find the receipt...so maybe it is running hot

the factory gauge doesn't quite reach 1/2 way but it seems to read low along with the gas gauge (with a new voltage stabilizer )

By the way...really NICE JOB with that cracked block you fixed...very nice

[maxfax]

That might be okay in 95 deg weather at 80% humidity, but it does seem a bit warm for a 185 stat in cooler weather...

Bad voltage stabilizer, grounds, various connections, the gauges, on and on, could cause those factory gauges to be low..  I don;t have alot of faith in them anyhow, no matter what the make of the car is..    (God I miss my Lincoln  )

Might pay to start by checking the t-stat..  I think everyone here knows how buggy they can be.. Last 195 Wahler I got consistantly opened at about 205F..     The outlet temp was around 230 when the darn thing would open..  The cheapo from Carquest (albeit cooler than I wanted, but it's what they had) seems to be working dandy...

I know every one of these little beats can be a little different, but generally I've noticed the temp at the outlet is generally 5-15 deg higher than the stat temp... Maybe 20 - 25 deg above on a heavy pull or hot day...

I'm still crossing my fingers and toes every time I drive the little Crackomatic..

[RustyCaddy]

well it is a Wahler so maybe my wife will be understanding one more time while the t-stat gets switched out for an older one that did work...she is a patient woman

thanks again and best of luck with your projects

[maxfax]

Before I got on here I though it was just me having crap luck with stats.. I'm not even going to say that all the stats I've had trouble with were Wahler either..  I've had alot of bad ones from Stant, Napa, ETC..  THey're probably all made in the same North Korean sweat shop...

Let us know how you make out!!

[rabbitman]

I've never heard of a 185F t-stat, for me it's been 180F and 195F.

I take that partway back.......my current stat is 87C, which equals 188.6F so your okay .

180F stat made the stock gauge sit in the middle, the 195F made it sit about 1-2 ticks from the red, and the 188.6F sits 3 ticks from the red until I stop working it hard enough then it'll drop to the middle .

I've heard of 160F stats......that would be so worthless.

[maxfax]

I'll correct myself...  "I now have a 188.6 F thermostat"..   I knew it was somewhere in there... 

I suppose if you lived in a climate that was constantly hot enough a 160 stat could be of some benefit..  But for the most part 160 stats are for gassers, and even on those that's a bit cold in most cases.  Heck, on really cold days my car doesn;t get above 160 with a 188.6F stat...

[RustyCaddy]

sounds like a 188 for me too then...so the 92 degree C is a little below 200 degree F...better find that receipt 

[RustyCaddy]

Well i started it up and ran the engine in the driveway with the coolant cap open and a turkey thermometer in the reservoir.  Let it get up to 150 degrees F on the turkey thermometer and compared it to the gauge in the cab...the cab read 165 degrees F.  i think the sender in the head might be off or it is sitting in a hot spot.  i had added a oil cooler to the NA so maybe the intake is picking up some extra heat before it reaches the head...idunno.  checked the T-thermometer in a pot of boiling water and it topped out at 212 degrees so it looks accurate (we are at about sea level).

anyhow, i figure if is reading a steady 208 on the cab gauge, the engine might be closer to 195 or 200 degrees

FYI...in case this comes up with someone else

crossing my fingers.

Funny thing is that the coolant gauge shoots up 20 degrees whenever i turn on the driving lights   

[Vincent Waldon]

Funny thing is that the coolant gauge shoots up 20 degrees whenever i turn on the driving lights   

That's a sign of a wiring problem...most likely the difference in ground potential between the block (which your temp sensor is grounded to?) and the ground you used for your gauge on the dash.  Turning on a heavy current load like driving lights is causing a change in the voltage drop across ground and therefore causing the gauge to change reading.

Could also be that your overall system voltage is dropping a bit due to a bad shared ground... causing the gauge to mis-read.  If you turn on your defrost fan full does the gauge move as well?

If you decide to troubleshoot further search for Tyler's thread on "voltage drop test"... the procedure in that thread should help you find your weak ground.

[RustyCaddy]

Yes, the defrost fan causes a change, as does the manual radiator fan switch.  thanks for the advice it makes sense.  the temp sensor and volt meter are sourced from the same wire (the unused rear window defogger) and the volt meter stays pretty steady which seemed weird.

i went ahead and JB welded the temp sensor into a plug i made from a 22mm oil plug that fits into the cylinder head inlet fitting where the AC temp sensor would go cause i couldn't get it leak proof with just teflon tape..   maybe (can't remember)/probably put the jb weld all the way out to the end of the sensor threads  so that might be a source of the grounding problem.

will put a grounding wire to the sensor woth a small clamp and see if that fixes it and if not a drop test is in my future.

Thanks for the help!

[Vincent Waldon]

Yeah, on my older MK2 the rear defrost circuit has huge dips in voltage, depending on load.

Shame, because it sure is convenient for gauges and such. 

[RustyCaddy]

"Yeah, on my older MK2 the rear defrost circuit has huge dips in voltage, depending on load."

As Homer Simpson might say..."dooh"

that did seem like a convenient place to wire in...will try something else