Os7213

Hi everyone,

Im thinking about replacing the water pump and thermostat on my 996 C4S 02'.
This work will be more a preventive maintenance then anything else as I have no leaks, no pump noise or anything that lead me to think of a possible failure but the car is now at 150000kms and I think it would'nt hurt if I change theses components.
The system has been flushed and fluid replaced in 2017 by the previous owner.
Im not tracking the car but do some spirtited driving (Who doesnt..)

I watched some good step by step tutorials available here on the forum and on Youtube.
I understand the points of getting a plastic empeller and a low temp. thermostat which is what I will get.

There is a couple points Im not confortable with or still have a doubt.

1- It seems that I need to loosen the engine carrier plate while supporting the engine.
For what I can understand I just have to support the weight of the engine, undo the bolts and move the plate back a little bit to make room to take out the pump.
When I did the engine mount it was really important to do one at a time, even with the engine supported just to make sure it would'nt move out of alignment.
Im now wondering why the entire engine carrier plate can be unbolted without risk of misaligment.

2- 50% of people seems to use gasket sealant on each gaskets... Im not agaist the idea if it can prevent leaks but I would'nt want part of that stuff in the system. what is your opinion on this?

3- Using a vacuum tool to refill the system... I think I get how it works. It create a vacuum in the system and the new coolant is sucked in leaving no air bubbles. I guess you can hook-up the tool, set a vacuum setpoint and come back like an hour after and see if the vacuum is still the same? Just to make sure your system has no leaks or is there another method method to check for leaks before refilling?

4- Torque on the water pump bolts. If I remember correctly the setting is 7 ft-lbs but I dont see alot of room to be able to put a torque wrench in there. Is there enough room or what is the technique you are using.

5- I will probably go for new water hoses clips if I change the hoses.. Should I upgrade to a better model or new stock ones will do it just fine?

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I prepared a part list just to make sure I have everything before attempting the job and I would like advises from you guys just to make everything is correct:

-Uview Airlift 55000 tool or similar tool
-Water Pump 99610601151
-Gasket water pump 99610634051
-Bolts water pump x5 90037801309
-Bolts water pump x2 90037817709
-Gasket thermostat 99610632650
-Bolt cover thermostat x4 90037803009
-Thermostat LNE, Motorad, Wahler 160deg (Havent decided yet)
-Coolant fluid from Porsche, ROWE, Pentosin
-Coolant plug 90021900701
-Coolant plug Gasket 90012314430

The rest of the list is for parts I would like to change while Im there.

Oil sump coolant gasket:
-Bottom: Gasket 99610631651 + bolts (x4) 90037803009
Top: gasket 99610632150 + Bolts (x2) 90037803009


I would like to change a few hoses... Here's a picture of my car with the hoses I would like to change if they are easily accessible with the engine still in place.
Can someone provide the parts numbers as I am a little bit lost with the different versions...



I think the 90deg hose on the extreme right is:

Water hose 99610623356

But Im not 100% sure.

as for the 2 others.. the one from the pump and the thermostat I have no clue as the technical drawings leave alot of interpretation.
I also dont know if they are easy to swap out..
Let say that they look brittle so if I can change them while the system is empty I will.

So if you ever think Im missing something please let me know!

Thanks for your time
Hugo

JTT

Hey Hugo,

When I did mine, I had the cats off, so I just removed the carrier plate completely. Made the job extremely easy as everything is exposed. I think if I was to do it again, I'd remove the cats again to avoid all the aggravation everyone talks about. No issues with alignment, the carrier plate doesn't have much movement once all the bolts are in place, even loose.

I installed gasket dry and haven't had any leaks, I believe this is the way it is suggested in the Porsche manual.

Yes, when you use a vacuum system, if it holds pressure (or vacuum in this case), it should be leak free. As I don't intend on doing this multiple times per year, I picked up my vacuum system from Princess Auto significantly cheaper than Uview.

All my hoses and clamps were good so I reused.

808Bill

https://www.pelicanparts.com/techart...eplacement.htm
Also recently did mine with cats off. metal gasket goes on dry. Coolant come in both forms, 5 gallons needed if doing a complete flush.
Follow Ahsais write up and you should be fine...https://rennlist.com/forums/996-foru...pump-tips.html

yelcab

Don't sweat it. It is not the hardest thing you will have to do on your car.

1. There is not a problem with both engine mounts off. They will come back just fine.
2. Pentosin concentrated coolant is what I use. Buy 3 or 4 1.5L bottle. Each bottle makes one gallon of coolant.
3. I would be very surprised if you could get ALL the old coolant out. The last time I did this, the car only took back 3 gallons of coolant
4. The metal gasket goes on dry.
5. The torque spec is low. This is where an experience hand is needed without a torque wrench. You don't want to ruin the thread.
6. Buy the hoses from a dealer. One of those hoses is actually a hose assembly with a bunch of hoses tucked in together. It will be more expensive buying from a dealer but you will get the right parts, and you drive a Porsche right? It costs.

There is plus and minus with either metal impeller or plastic impeller. Metal impeller grinds the case if the bearing is bad. Plastic impeller breaks off and sends pieces everywhere. The way to avoid all problem is to change the water pump every 60K miles before it breaks. Treat it as preventive maintenance, which is what you are doing now.

Best of luck

808Bill

Get the Pierburg pump. It's impeller is a composite with some sort of metal blend that withstands breaking of the fins like the old ones.

Os7213

Thanks for your advises guys.

I will probably end-up using Pentosin coolant as it is easily available and correctly priced.

as for parts Im really interrested in the LNE kit that come with a Pierburg pump, LNE thermostat, gasket and bolts
https://lnengineering.com/products/m...riven-csp.html

Price for price I think it worth it as I would have to order all parts from different sources and end-up spending potential savings on shipping fees.

i will do all the math but I think I found exactly what I need at the right price.

808Bill

^ good price for what you get. I wish I went that route a few weeks ago!

Dripola

I did this a couple of months ago and still feel it was the most unpleasant job I have done on the car. Check you bolts on your cats, if they are rusted you may have issues removing. May be worth using a block of timber to keep the space between the block and the carrier. Makes it easier to get the pump in and out. Some bolts can be torque wrenched some not.

consider doing the third radiator now since you’re draining some coolant.

good luck and enjoy.

yelcab

That LNE kit is a good kit for a good price.

Os7213

For the space to get the pump out I think I will take off bumper, cats and engine support plate.
All my exhaust hardware is brand new so Im confortable removing everything and re-use the hardware.
With the labor saved I think I will invest in a nice support table for the engine which will make the job alot easier.. More time consuming yes but alot easier.

Picture from a fellow member found while doing my research thanks!

Os7213

Hi guys

Just a quick update.
I have been able to figure out the P/N for the different hoses I would like to change for new hen changing the water pump.






Waterpump 3 ways hose:
996-106-850-06 + 996-106-851-03

Thermostat housing to hard coolant line: 99610683204

90deg water hose from oil pump side:
996 106 233 56


Top side of the oil pump 996 106 831 01

So Im wondering how to disconnect the one from the top side of the oil pump from the picture above.
I understand the clip side but Im wondering if the other side can be done with the engine in?

Same thing for Thermostat housing to hard coolant line: 99610683204
Anyone have changed this hose with the engine in and can share his experience?

Thanks
Hugo

808Bill

If you can see and touch them then yes they can be done. Spring clamp tool is a must. Channel lock pliers work fine if you have the room.

Os7213

Spring clamp tool ordered! Thanks Bill

Can you explain me how to disconnect the hose that has no clamp on one end?

Also what do you think about vacuum refill system?
It seems to be easy to use and refill the coolant without air bubbles but Im concerned about hoses getting collapsed.

Thanks
Hugo

808Bill

I sent you a link to Pelicans Technical section, did you not explore it?
It's right here, see figure 10 at the bottom
https://www.pelicanparts.com/techart...eplacement.htm

Argeo

Just did mine this weekend. The compressor trick at 10psi blowing coolant out the thermostat worked really well. I replaced the 90 degree hose on right too. A little coolant cane out with air and the thermo reconnected.
A must is a 10mm wrench that has a bend to get at wp 10mm bolt on right side towards the middle. I was able to torque all but top left bolt.i should have done when engine carrier loose. That black line that blocks the wp from sliding down needed a little wrestling to get out too. Good luck.