jksymz75

I flushed and filled my coolant and now my temp shoots up to the top mark (before the red) when putting even minimal load on the car on a hot day.

And then the fans come on and the temp goes down. It never gets to the red but it has trouble staying down.

If I turn on the heat it stays pretty reliably between the two middle marks. But should it be dead on or does the temp always fluctuate in our cars? On my old e30s the needle stayed dead in the middle at all times.

I've tried bleeding the cooling system by the ways described - elevating the nose, turning on the heat, leaving the bleeder open for 30 mins, squeezing the hose, gunning the engine... - but it seems that what my car is doing is consistent with air in the system. Am I right?

And if so, how are you bleeding your system? Do I need to invest in a Air Purge and Refill tool like the Airlift uv550000?

One note: when bleeding last time, the coolant stopped coming out of the bleeder after being open for about 20 mins despite the needle being above half. Squeezing the hose to the bleeder, it felt empty. Only when I revved the engine did it come spurting out again. Not sure if this is normal. Coolant might've just been low from bleeding out for so long.

thomasmryan

how old is the pump? sounds like its not pumping. see if there is temperature difference between the upper and lower hose.

sometimes the impeller comes loose...a bad thing.

odurandina

Free the air pocket with the top-of-engine valve.
If the heat persists--then you'll no for sure.
Hope it's not the HG.
re; HG's: Never over-rev the son of a bitch.

jksymz75

PO said water pump was replaced before I bought at 75K miles (20K miles ago) but there's no paperwork for it. He had some mech doing side work for him (he had multiple P cars) so I'm 50/50 on believing him.

What makes you think it's the water pump?

thomasmryan

You can pull the thermostat and put it in a pot of water on the stove to see when it opens but sounds like the coolant isn't moving. Since the belt tension is set by the tensioner, it's probably not a loose belt. Composite impellers do fail. Set the engine to tdc and take the timing belt off. Spin the pulley and see if it feels like it has resistance like it is pushing coolant.

odurandina

The Mexican H2O pumps aren't the best.
Failure after 20~25K miles isn't out of the woods. Some parts are really that bad.
Also, overtensioning belts can cause premature failure.
High end cars have their service records.968's certainly fit in that category.
It's easy to keep the work sheets for any high end car organized in a folder
so they can be passed from birth to part out, and from owner to owner.
Repairs really can't be considered gospel true if they don't have the work sheets
to prove it..

ste1999

Normal on my car is the temp staying rock steady mostly on the quarter mark while running and just above when idling hot in traffic and using the fan. It never fluctuates or goes that high.

I refilled my coolant a few times recently due to issues with a heater valve. Each time it was pretty straightforwards and not as big a challenge as seems to be implied by some comments online. Heater valve should be open. All I did was fill as much as possible via the reservoir, jack up the front to get a slope, then disconnect the top hose at the cylinder head end (easier than the radiator end) then fill the head and block to overflow at the takeoff using a funnel with a bit of hose attached, then mostly fill the top hose itself, reconnecting after. Finally the car was bled on the level both static and running, the reservoir should be filled right into the neck higher than normal for the process. The procedure worked fine every time, no air locks.

Guess your symptoms may indicate other problems if block and hoses have been filled right,

Steve

thomasmryan

93F day.

Isaacsracing

It was only about 70 F today here, but very humid. I was running the A/C and the temp gauge was below where Thomas shows in his picture.

I recently did a coolant flush and replaced with Pentafrost NF and the cooling has been rock solid right around the mark shown in Thomas's picture. Prior to that flush I would get some fluctuation from that mark up to the higher mark and back down again. At the mark when moving, but higher when sitting still. But with a good flush, it stays at the lower mark.

jksymz75

I flushed and filled with Pentofrost NF. I appreciate the comments, it gives me something to look into when I get another chance to get in the garage. I'm wondering if the water pump or thermostat are the culprit, but I'm also not convinced that it's properly bled. When I drove last time, temp stayed down a bit more than previously, but it was also not as hot that day.

When I see Thomas' picture of his needle staying at that first mark I get jealous.