Quick Question about Filling Coolant

Technical questions and answers concerning all models of VW diesel vehicles.

Moderator: Fatmobile

Post Reply
TylerDurden
Turbo Charger
Posts: 1285
Joined: Tue Dec 22, 2009 1:01 pm
Location: Michigami, USA

Re: Quick Question about Filling Coolant

Post by TylerDurden »

I can predict questions!
Nate_ o will ask:
So I know that you are supposed to fill your coolant by starting the engine and letting the air work itself out of the system. My question is that with the engine running should there be coolant flowing into the overlow tank? If so is it all the time or only when the thermostat is open?
The little tube should always pee into the tank, regardless of thermostat temperature.
Have a nice day.


'91 Jetta ECOdiesel TD - clean & complete (less motor/tranny) for sale

'82 Westy Vanagon 1.9 N/A - 23.5mpg
'86 Jetta TD - 45-50mpg
'81 Dasher Wagon 1.6 N/A - 52mpg
'84 Wasserboxer - DOA, parts donor
'94 Passat wagon VR6
'03 Jetta TDI wagon 230K, 52.3mpg
'89 Jetta N/A - 51mpg
'82 Caddy 1.6 N/A - Sold
nate_o
Cetane Booster
Posts: 38
Joined: Sun Jul 21, 2013 1:56 pm
Location: Ohio

Quick Question about Filling Coolant

Post by nate_o »

So I know that you are supposed to fill your coolant by starting the engine and letting the air work itself out of the system. My question is that with the engine running should there be coolant flowing into the overlow tank? If so is it all the time or only when the thermostat is open?
91 VW Jetta 1.6L Turbo
nate_o
Cetane Booster
Posts: 38
Joined: Sun Jul 21, 2013 1:56 pm
Location: Ohio

Re: Quick Question about Filling Coolant

Post by nate_o »

HMMMM so my little tube isnt "peeing"
Water Pump?
91 VW Jetta 1.6L Turbo
TylerDurden
Turbo Charger
Posts: 1285
Joined: Tue Dec 22, 2009 1:01 pm
Location: Michigami, USA

Re: Quick Question about Filling Coolant

Post by TylerDurden »

Presuming you have an upper radiator hose with the bleed tube going to the tank...

Most often, the little restrictor in the purge hose gets plugged... it looks like a lump in the tube near the tank, but it is a small device inserted to make the tube ID smaller there. I'd try to clean that out with a thin wire.
Have a nice day.


'91 Jetta ECOdiesel TD - clean & complete (less motor/tranny) for sale

'82 Westy Vanagon 1.9 N/A - 23.5mpg
'86 Jetta TD - 45-50mpg
'81 Dasher Wagon 1.6 N/A - 52mpg
'84 Wasserboxer - DOA, parts donor
'94 Passat wagon VR6
'03 Jetta TDI wagon 230K, 52.3mpg
'89 Jetta N/A - 51mpg
'82 Caddy 1.6 N/A - Sold
82vdub
Turbo Charger
Posts: 4922
Joined: Wed Jun 20, 2007 1:44 pm
Location: Green Bay, WI
Contact:

Re: Quick Question about Filling Coolant

Post by 82vdub »

I've always removed that restrictor in the line. The oriface is so small that nearly any debris in the cooling system will plug it. My Rabbit didn't have a restrictor in the line, so this didn't show up until later likely with the mk2 chassis.

Even if the restrictor is removed, try blowing air through the line first. I've had the larger line iteself plug up when a twig got into the cooling system (no idea how that happened either).
Everybody else lists their cars here - but not me.

I have too many to count
greg lousy
Turbo Charger
Posts: 230
Joined: Thu Apr 05, 2012 12:22 am
Location: Rhode Island

Re: Quick Question about Filling Coolant

Post by greg lousy »

The actual plastic nub on the coolant tank plugged on me once... some kind of mysterious silicon type stuff... worth cleaning with a wire while your in there

a good check is to take the little hose off the reservoir and blow into it. you should be able to blow air into the radiator and hear bubbling. If not, I'd suspect the restricting fitting. Also, revving while looking for the stream should increase volume and make the stream more noticable
Various vehicles in various states
Post Reply