engine temp vs speed question...

[irdiver]

hi all

i just finished getting a full turbo engine into my eco diesel jetta with 5 speed.
still running the k14 turbo due to the k24 i got with the engine needing a rebuild, stock exhaust/intake, etc no other mods yet.  so on the maiden voyage on the highway here in florida i notice that as long as i stay 70mph or under the temp sits on the second to last bar on the temp gauge, anything over 70 and it starts to creep up to the last bar.  the quesiton becomes is that normal for these cars or do i have a cooling issue that i need to fix?  HELP!  a max speed of 70 here on I75 will get you killed from people and trucks trying to run you over.  suggestions please!

[jtanguay]

i'm not sure the relation to temp vs bars, but I do know that optimum running temperature for our diesels is just over halfway.  If its running too much more than that, you have to ease off the pedal, and fix the problem before you kill your motor.

Checklist:

1.  Check the obvious (fluid levels, leaks)
2.  Check your air filter, yes restriction will make your little engine work harder for nothing, producing more heat!
3.  Check the fan by running your engine until it gets hot (1 and a half ticks past middle I believe) enough to come on (easy way) or jump it with a live 12v wire to see if it comes on.
    *** If fan doesnt come on then you need to check the temperature sensor located on the left hand side of the vehicle on the bottom of the radiator (3 prong sensor)  if both are okay, then your relay/fuse are most likely bad.

If all of the above are fine, then you need to do some advanced troubleshooting.   You say the motor was a 1.6TD with a K24 turbo.  Maybe you need to turn the boost enrichment down/fueling or install a better flowing exhaust?  Do you know much of the history of the motor? Maybe it was timed incorrectly?  If the K24 you were going to swap in needed a rebuild, I would question the state of the motor itself...

[wyldman]

These little motors normally run just a hair over the halfway mark.If your pushing it on the highway,they will run hotter,normally almost 3/4 of the way up on the gauge.

[irdiver]

i will have to check the fan sensor on the radiator, i put a new one in and i know it works but there were two choices in temp, i chose the higher temp one (kicks on at the 3/4 line), i will put the lower temp version in and see what happens.  in the city the engine sits just over half but on the highway up to 3/4 and over 70 starts to creep to the last line.  so im going to open the exhaust, put in the k/n air filter i have and if i can find the room between the a/c condensor and bumper finally install the intercooler i have from an audi.  sigh projects are never done....  thanks all

[HP]

You guys say the normal operation temp for these motors is a little bit above half the scale. In my Golf, it normally runs, I'd say 3/5 or a litle more, the scale. Half, the maximum (sometimes). This is in the city.
On the highway, going 100-130km/h, the temp is allways stable, below half the scale too.
Only when in long grid locks, the needle eventually "climbs" up to 3/4 of the scale, to return a little later to the half posistion due to the cooling fan that starts to work (you can even notice the idle lowing down a bit during that).

This is how it happens allover the year, except in the Summer, when ambient temperature peeks some days at more than 40ºC. In this time of the year, the needle is normally closer to the half, or on it, when it's real hot. On traffic jams, the temp raises, of course, faster, but never passes those 3/4 (well, maybe a very little more in some occasions...) as I said above.

Does this indicate my engine is nicely cooled, and the way it should be (despite 330.000km), or is it too strange it could sugest the temp gauge is malfunctioning (hope not   ) :?:


sorry for the long post.

[jtanguay]

you want your motor to run at around 87C or even 90C.  

[HP]

That means the middle of the scale? Mine does not display any figures.

[jtanguay]

yea... i really wish vw would have placed some temp numbers rather than ticks...!  I believe the 3/4 is 90C

[TDForNow]

irdriver, I think you've got a thermostat stuck partially open, but not opening the rest of the way. My Quantum 1.6TD w/stock T-3 is fueled as heavily as I dare without an intercooler and I'll run 70-80mph 60 miles each way to work, hills and all and the temp guage never goes above 2/3. The only time my fan comes on is at just above 3/4 and that's when setting at a light after hard squirting around town

[irdiver]

huh ok i just replaced the stat too.  huh wonder if i have crud in my radiator, the last engine i just took out had the same hot issues, currenly the fan kicks on once the gauge hits the second to last line (3/4ths) so i think that may be right, but the radiator will be the next thing to pull and clean out

[jtanguay]

if your car has a/c the fan has 3 speeds.  hi/lo and the a/c speed which is restricted by a resistor.

I believe if your temp goes above 3/4 the hi speed should turn on.   maybe your low speed is busted?

it could definitely be the radiator.  deposits on the interior metal surface don't like to transfer the heat  I'm still considering getting a new radiator, or trying to clean out the one I have...

[HP]

And the low speed should be on at which temp?

[jtanguay]

not too sure..  I think its something like 90C low speed and 93-95C high speed.  but how the heck do you relate that to the ticks on the gauge? lol

[HP]

:lol:  I can't!
But it seems you can!
 [quote="jtanguay" ] I believe the 3/4 is 90C [/quote]

Yeah, VW should have put some numbers on it...

[jtanguay]

might be wise to invest in a cheapie temp gauge with some numbers on it