Ben Allison

Already replaced water pump and thermostat.

1984 US model.
Car overheats after about 15-20 minutes of driving (goes past the third tick - I don't let it get into the red).

The radiator hose from the thermostat to the radiator is "room temperature". I can touch it with my hand.

The old water pump had a worn bearing but was otherwise functional.

Have had a slow leak for a while. I have to add coolant/water every week or so, but it's intermittent.

What else could be causing a lack of coolant flow to the radiator?

Dave H.

did you put the t-stat in the right way?

Ben Allison

Thermostat is on the right way (note: this overheating problem started before I replaced water pump and thermostat).

Did some more investigation (and forums searching) and I think the problem might be the radiator. Top 1/3 is hot, bottom 2/3 is icy cold. Clogged? Any way to fix this short of replacing the radiator?

Garth S

On the '84, the rad can be easily removed - which is step #1 , if this has not already been done.
There may be a huge wad of leaves, dead mice, whatever crammed between the rad and AC condenser which are now spilling out - ie., verify airflow.
Next, verify water flow through the rad with the max flow you have available. By blasting cold hose water through - or hot if you have the hookup, you can 'feel' the flow pattern through the rad. If the bottom tubes are plugged, perhaps a rad shop can chemically clean it for you; otherwise, a new rad for Xmas ....

A cheap gallon of household vinigar poured into the rad for an overnight soak followed by a flush will not hurt the rad - and may restore flow if that is the issue.

Mrmerlin

Did you replace the black sealing O ring thats pressed into the rear portion of the T stat housing? , Is the sytem full?
To get the cooling system full open the heater and fill the resivour to just over half full tanke the car for a drive with the heater open/on it takes about 5 miles or so then check the coolant level let the car cool off before topping it off

dr bob

Plan to rtemove the radiator and clean or replace. The cold-at-the-bottom symptom means the tubes are blocked. Blocked airflow would cause the radiator to be hot in that area, FYI. The vinegar trick is interesting, but is not likely to clear fully-blocked tubes. By the time the concentration is high enough to clear the calcium salts, it's likely that you'll do other damage to the block/heads and head gaskets. Best to have the radiator cleaned professionally.

Be sure to pull the block drains and get the crud out of the bottom of the water jackets. Some owners have reported that they needed to poke into the galleys to get accumulated deposits out.


Be sure to use a good coolant/anti-freeze, diluted with distilled water only.

928ntslow

I think I have a similar problem with my 82 Euro. The expansion tank boiled over yesterday while we did fuel and idle adjustments. Both rad hoses were warm but rad was cold. After a few minutes of shutting down. the rad warmed up as if the flow went backwards when it equalized and hot fluid went up into the rad. I am gonna pull it and had tit cleaned.

largecar379

Ben--

I have a radiator just freshened if you need one----

--Russ

the flyin' scotsman

I've a similar issue also except the entire rad is cold, as is the engine as is.................

the fever is coming on

jpitman2

Doesnt the thermo O ring go in front of the thermo, clamped by the outlet?
jp 83 Euro S AT 51k

Stephencs601

A word of advice, change the three piece radiator. I have a 1984 and was running a little hot. I replaced the radiator with the one piece unit from 928 Intl and have not regretted that decision. The car runs cooler and no more possible leaks from side tanks. Best money I could have spent.

VWaddict

"tit cleaned"?

...I'm gonna have to see a video of that...

Landseer

Three pieces.

O-ring for housing, thermostat, and special rubber-covered metal seal that fits behind the thermostat.

Thermostat opens and contacts this back seal.

928ntslow

Dang, what happened there??? I'd like to see that myself!