A surefire, fool proof, can't fail coolant fill technique

[rlux4]

I'm posting this here in addition to Mira, because it worked so well for me I don't want anyone to miss it if it can be useful.

I had trouble getting the system bled out when I put in a new thermostat. The
problem was as I filled the radiator the coolant would get air-locked before
it reached the level of the thermostat from the bottom (from the radiator)
hose. After following the manual instructions and various forum guidelines, I
still couldn't get circulation.
The lower hose and radiator stayed cool as the engine went up past 190°. The
solution (suggested by Ace to give credit) was to drill a 1/8" hole in the
stat valve head:


I then filled the radiator (still easier with the front end raised) until it
was full. I then undid the bleed screw on the "T" and used a small funnel to
fill into it till it was showing standing coolant.


Then I filled from the "T" I put in the upper heater hose.


The last step was to disconnect the small hose going to the throttle body
heater and using the small funnel again, fill it. It is the hose that is
closest to the camera. I use a rubber vaccuum cap on the heater body nipple
until I have the hose full.


Using this method, it doesn't need any more burping than what you do on the
upper hose as you fill the radiator.
As I have posted, when I replaced the stat on the wifes Caravan, it had a
bleed hole in it from the factory. I've run the car several hundred miles
since I did this and it maintains perfect temperature in all conditions.
I hope this helps.
Ron

'82 2000, after 26 years between Spiders


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[kristoj]

That last step only applies to those wonderful FI cars. If you bleed the system at the throttle heater plate (the highest point in the system), you really don't need a flush Tee in the upper heater hose.

[rlux4]

Oops. I missed that John, thanks, and right on.
My "T" on the heater hose got put in prior to drilling the hole in the stat in an effort to get the system working.
Ron

[So Cal Mark]

on the carb models you can use one of the choke heater hoses for the final fill

[rlux4]

My main point was that no matter what I did, I couldn't get the coolant up to the themostat on the radiator leg. I filled it up to the top of the hose before connecting the stat, still wouldn't go that last couple inches. The little hole made all the difference. I know it's being done all the time by others without the hole, but I just couldn't get circulation without the hole to allow the coolant to get up to the closed vave in the stat so that it could be there instead of air when the stat opened. I think my water pump may be ready for replacement, the intermittent whining noise is probably coming from it, and maybe it has something to do with it not creating enough suction to bring the coolant up that last couple of inches. Once I have circulation though, it works perfectly.
Ron

[So Cal Mark]

I've been driling holes in stats for years, but some of the new aftermarket Fiat stats come with a small bypass so the hole isn't needed.
If your water pump impeller is that worn, you should have poor circulation

[rlux4]

I don't think it is Mark. When I had the thermostat bypass in before installing the new stat, I had the radiator cap off and the coolant was flying through the radiator. I'm just looking for an excuse to change out the water pump, thinking it is what is causing the whine.
Ron

[ventura ace]

One easy check to find out, Ron: remove the v-belt (water pump, alternator). If the whine goes away, it was either the belt or the water pump or the alternator.

Alvon

[rlux4]

OK Ace. But call me in a day or two to remind me to put it back on. (Memory isn't what it used to be. I think.)
It is a new belt though, so that's out of the eqaution. I've known you can check it that way, it just seems to be one of those things that I haven't gotten to yet. So much fun to have. So little time.
Ron

[mdrburchette]

That non-Fiat mechanic didn't tighten your timing belt too tight, did he Ron? That would cause a whine.

[rlux4]

The whine has been there since I got the car Denise. It fades out after a minute or so. I've had the belt off since he helped me with the head gasket. I had the belt off this morning to check the alt. and water pump as Ace suggested, and suprisingly, it was still there. Oil pump, maybe?
It will reveal itself one of these days, until then I'll just live with it. The worst part is when I start it, I get asked "what's that whine?" .... I dunno.
Ron

[ventura ace]

The noise that Ron is talking about is a weird one. I don't believe I've heard it before on other cars, so it has me stumped. We ususally thing of a whine as more of a higher frequency noise, like the sound a woman makes (women tend to whine, men tend to grumble ) It's a man-noise with a lower frequency (maybe 50 - 100 hz). It definitely has a pulse to it that you can detect. Maybe it is the teeth on the oil pump gears or the helical gear betweeh the aux shaft and the oil pump, as Ron suggested.

Ron, you could slip the oil pump drive gear out, and crank it up for just a few seconds to listen for the sound (preferrably after the engine has run just a little to put fresh lubricant throughout the engine). Only do this for a few seconds, so you don't ruin any bearings. I can't remember, but you may be able to slip the drive gear out without removing the aux shaft. It's a short little helical gear that sits on top of the splined end of the oil pump shaft. It's held down by the blank-off plug near where the dip stick goes into the block.

Alvon

[rlux4]

Quoting Ace: "Maybe it is the teeth on the oil pump gears or the helical gear betweeh the aux shaft and the oil pump, as Ron suggested."
I suggested that?
Hell, I don't even know what a helical gear is!
All I know is, my car was made by Fiat, not Sikorsky.
Ron

[So Cal Mark]

if you take Aces' suggestion and run the engine without the oil pump, call me and I'll be happy to sell you another short block

[rlux4]

Do you think it would hurt the engine if it were warmed up first, and then only run for a second or two? Seems like it would take longer to do any damage, assuming a good, clean engine and oil.
Ron