1984 mk1 jetta overheating and heater problems

monkey man · Last edited by monkey man on Wed Feb 19, 2014 12:31 pm; edited 1 time in total

Just got my jetta four months ago. Replaced the water pump. And fan switch activated by water temp. No problems until winter hit. My heater only blows warm air half of the time. And the car over heats if its parked and idling as soon as I get halfway down a street it has already returned to normal operating temp.

1.8l 8v cis gas motor.
No ac
Metal impelor on water pump. No wobble on the shaft.

crsmp5 · Posted: Tue Feb 11, 2014 10:56 am Post subject:

so many reasons, too little info...

engine
rad style
did you use metal impeller or plastic on wp
ac or not

to me sounds like air pocket...

rad not flowing or improperly filled, rad style...

or plastic impeller loose

i know my fav this season... wally world antifreeze mixed to 50-50 is good for 25+*f.. not -25....

monkey man · Posted: Tue Feb 11, 2014 11:16 am Post subject:

Radiator has an over fill tank with radiator cap on overfill tank.
50-50 mixture done with pure antifreeze and water using a antifreeze measuring tool.
1.8l 8v cis. No ac.
I'm pretty sure it was a metal impeller but I'll check that once I get it into the garage.
The over fill line that leads from the top of radiator to overfill tank flows fluid when car is running. Tbh Im not sure if tthat's good.

crsmp5 · Posted: Tue Feb 11, 2014 1:47 pm Post subject:

that is coolent flow, good thing, seen the nipple at rad plug up and cause said issue... see your gettig how info works..

now the bad news... its got flow, so for it to do what your sying, its almost got to be bad headgasket.. or impeller quits spinning when you start to drive.. or thermostat is stuck closed... but with how cold things are this side of country, heatercore should work as radiator.. just no idea how cold where u are..

pull thermostat, use screw driver thru thermo hole to check impeller... and then you kinda check 2 of the 3 off...

not common for gasser to eat headgaskets... but if original its possible due to age.. in theory tyou can use a metal aba headgasket if head/block smooth and not horribally pitted..

monkey man · Posted: Tue Feb 11, 2014 2:08 pm Post subject:

I'll be sure to check as soon as I'm able.
What are the other signs I should look for, with a blown head gasket.

73sports · Posted: Tue Feb 11, 2014 3:50 pm Post subject:

Sounds like the rad fan is not coming on.
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monkey man · Posted: Sun Feb 16, 2014 1:22 pm Post subject:

I'm pretty sure its thermostat. Just let it idle till the needle was at about 3/4 the bottom radiator hose was still cold so I think its the thermo stat. On a side note when iI tried starting it yesterday it acted flooded and I would have to give it a lot of gas to start it. I had to make it idle at 1000 rpm for 5 min today to get it to idle normal.[/img]

crsmp5 · Posted: Sun Feb 16, 2014 2:54 pm Post subject:

i suggested changing it and checking with screwdriver the impekller being loose... if both good, i expect headgasket... headgasket may make it start crappy... but till you check you will never know...

monkey man · Posted: Tue Feb 18, 2014 10:02 am Post subject:

I'm putting the new thermostat in today. The water pump is perfectly fine. While im at it im gonna change the oil to make sure there are no irregularities, i usaully use 10 w30, my question is what oil should i use synthetic, non synthetic, castrol, etc. Im unsure about the mileage it had a motor swap by a previous owner, but my chassis has 165,000 miles. I'm hoping the motor has less than that.

crsmp5 · Posted: Tue Feb 18, 2014 11:00 am Post subject:

10w30 is ok in dino oil if it does not get real cold.. if your in mountains with single digits, synthetic or 5w30 for winter..

depending on temps... i use 15w40 rotella for dino.. and their synthetic in times i want that in say a tdi...

oil type is a temp vs how much it uses aspect to me... if it burns it fast, no reason... just wasting money if its a running oil change..

monkey man · Posted: Tue Feb 18, 2014 11:13 am Post subject:

Its pretty dirty oil. Don't know when it was changed last. It hasnt been below 30 the past week. But with Spokane weather I have no clue if it will get cold again or keep warming up. Spokane is 1843 feet above sea level.

crsmp5 · Posted: Tue Feb 18, 2014 12:51 pm Post subject:

no idea on your weather... but i can say with out doubt... 15w40 rotella, 15*f better have block heater... else the tar to thick to allow crank to spin fast enough to light up.. this is old idi stuff.. my tdi sits when under 30*f unless im on roadtrip..

monkey man · Posted: Tue Feb 18, 2014 1:15 pm Post subject:

OK I started her up. Idle troubles had to hold a 1000 rpm for 4 minutes. Ran until operating temp turned on heater fan and smoke came out of the vents. Ran until thermostat should open still no dice. Shut it off 10 minutes later started slight problem motor usually turned the alternator on when its warm had to bring revs up a little so aptsstarts working then let of and idles fine, tried the heat still smoke coming out of the vents, thermostat still not opening.

73sports · Posted: Tue Feb 18, 2014 3:03 pm Post subject:

Smoke or steam? If you are getting that through the vents, I'd think the heater core is leaking. Have you pressure tested the cooling system?
_________________
I will never lie, but sometimes the truth changes.

Central Jersey VW Society

monkey man · Posted: Tue Feb 18, 2014 3:09 pm Post subject:

It fogged the windows automatically. I have not pressuretested it.

crsmp5 · Posted: Tue Feb 18, 2014 5:35 pm Post subject:

u expect a diesel thermo stat to open in 10 min on a cold day... good luck... maybe after 30 or so with no heat turned on.. the core will cool like rad way before thermostat opens..

this is also why the steam.. till it gets hot tenough to DRY the heater core.. it will smoke.. even if its got a slight moist leak of a couple table spoons.. a month..

got ac or not?? if ac.. the box could be full of water.. the drain plugs up.. does same thing... lots of steam..

monkey man · Posted: Tue Feb 18, 2014 6:01 pm Post subject:

Its not diesel. Its a 1.8l 8v gas motor.no ac

monkey man · Posted: Thu Feb 20, 2014 1:34 pm Post subject:

I have a 190°f thermostat in it right now is that too high.

crsmp5 · Posted: Thu Feb 20, 2014 6:37 pm Post subject:

80*c is what i use, no idea in f.. 87*c is normal temp... ... and i knew it was gas... too many diesel threads...

i cannot say even 10 min on gasser, takes a good 3-4 min to get warm enough to turn on o2 sensor system... you can hear a change in the frequancy valve.. if it coes on too soon they tend to run lean and stall..

monkey man · Posted: Fri Feb 21, 2014 1:17 am Post subject:

80°c is 176°f . so 190° f is to hot for a thermostat?


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1984 mk1 jetta overheating and heater problems
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