Sanity check - my coolant went about a quart low after WP/Thermostat change - air? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

steved0x · 01-12-2015, 11:14 AM

I just finished up a water pump/low temp thermostat/UD Pulley last night and this morning I took it for a drive. About 15-20 minutes out the coolant light starting flashing slowly and the temp stayed right on the 1 part of the 180. I was staying close to home for the test drive so I immediately came in, and found that the coolant was about a quart low. Trunk was dry and no gushing out by the back wheel. I added about a quart to top it off, and took another 20 minute drive, during which the level stayed full and did not drop, and my light did not flash.

I used the Airlift vacuum tool to add my coolant but I am thinking that maybe a small quantity of air remained in the system and burped its way to the top (I did not do any bleed procedure after filling the coolant with the tool). Should I flip the bleeder valve and go for another drive, park nose down, all the tricks I have seen for bleeding (including following the Bentley procedure

) to make sure I have gotten all air out?

When I used the airlift tool I took it up to 25 on the dial (per the instructions) and let it sit that way for a few minutes, during which time I lost no vacuum and the reading held steady. I know that vacuum is not the same as a pressure test but I felt pretty good about that.

What do you guys think? Leak some where? Or just a little air in the system that came to the top and dropped my level, hopefully as a one time thing?

Thanks

Steve

PS For a data point my waterpump was the original pump (2000 Boxster 115,000 miles) as evidenced by the fact that I had to cut the three metal webs in order to get the old gasket off. Vanes were intact and there was no play in the bearing. It did spin just a little easier/faster than the new pump. On the inside it looked brand new, and the outside was pretty good too. I feel like I got a good life out of it, but since I had no record of it ever being changed I figured it was time.

Two of the water pump bolts are longer than the others. The water pump comes with 2 dowels to help align it and also you can pop the gasket onto the dowels and the dowels hold the gasket as well as to align the pump. The two longer bolts go with the two holes that have the dowels. I was paranoid when starting the job to make sure I got those two bolts back in the correct spots, but once the pump was off it became apparent. I was able to torque every bolt except the rightmost one, so I just tightened it nice and tight by feel.

nicecar · 01-12-2015, 11:35 AM

had a coolant leak on my lr3, after I reapaired and filled all was good untill next morning down about 2 cups been fine since...read other posts where same thing occured

san rensho · 01-12-2015, 06:14 PM

Next couple of times you start the car from dead cold, lift the purge valve bail, then let it back down once the car warms up. Check coolant level and top up as necessary.

steved0x · 01-12-2015, 06:39 PM

Quote:

Originally Posted by san rensho

Next couple of times you start the car from dead cold, lift the purge valve bail, then let it back down once the car warms up. Check coolant level and top up as necessary.

Will do, thank you.

nicecar · 01-12-2015, 09:06 PM

I forgot to mention I had to bleed the system via a bleeder valve, however even after bleeding the system it dropped over night. Now it reads low coolant because coolant tank sensor failed. The original leak was a failed bleeder valve made from plastic. Using the rover forum for diagnosis, these 2 plastic parts fail alot. I had a coolant leak on my 02S which was a failed plastic quick release fitting on top of the motor. Went to Brumos for the part which they could not identify, The mechanic came out a said not to replace it with plastic crap go to NAPA and get a copper coupler,which I did. I knew not what I was getting into with the rover or box but the forums keep me in the know. I know I havent been much help but I do feel your pain. As my r.v. guy says "it aint the fffin space shuttle. When bleeding the system it did have to get to temp with the heater on full blast to get the thermostat to open. I do not know if the heater has to be on for the Box but it sonds logical

steved0x · 01-15-2015, 05:21 AM

Quote:

Originally Posted by san rensho

Next couple of times you start the car from dead cold, lift the purge valve bail, then let it back down once the car warms up. Check coolant level and top up as necessary.

I took a couple of long drives, including one in which I flipped up that bail before starting out and then I followed the Bentley bleeding procedure with revving and so forth as best I could while driving, and so far all good, no more drops in coolant, and my temp is right on the 1 of the 180, the needle maybe at 330 degrees (like pointing toward the 11 on a watch)

Thanks

Steve

clickman · 01-15-2015, 06:41 AM

Interesting. I've used the Uview on the Boxster a few times now, and it's been perfect every time. Never had to add more...

JFP in PA · 01-15-2015, 08:39 AM

Quote:

Originally Posted by clickman

Interesting. I've used the Uview on the Boxster a few times now, and it's been perfect every time. Never had to add more...

You are correct, if the Uview has been used correctly, and the system is tight, you should not have to add coolant later unless something has gone wrong after the refill.

Perfectlap · 01-15-2015, 10:10 AM

I'm curious to see what your low t-stat experience is like. Seems that needle takes much longer to get past 12 o'clock since I made the switch. Very different from before. Or maybe I need to drive differently.

p.s.
to people reading this who've not touched the cooling system, replace that coolant cap.
That $20 staying in your pocket can ruin your engine...

steved0x · 01-15-2015, 06:04 PM

The needle stays around 11:55 most of time. It only went slightly above when I did a few hard pulls but settled right back down. Today was in the 40s and it never moved past 11:55.

steved0x · 01-16-2015, 05:53 AM

Here is a photo of where it sits now.

Perfectlap · 01-16-2015, 10:53 AM

we had a few 95+ days this summer, about the only time I saw that needle near 1 o'clock.
With the old t-stat that was a regular thing. I wonder what effect this has on the engine. More longevity? Less risk of an event? Both? Neither?
I know that low temp t-stat is SOP on the newer Porsches.

steved0x · 01-19-2015, 07:59 AM

To close on this issue. After two long drives (20+ minutes) with the bail flipped up, I had to add about another cup of coolant after the first drive, and none after the second drive. (My conclusion is that I did something incorrect and left some air in the system even using the Airlift. I wonder about the hose that draws in the coolant. Maybe I should prefill with coolant? That would be one source of air right there, but not a quart worth). I then drove to Savannah, GA (180 miles) and did a 2 day DE at Roebling Road Raceway with Florida Crown PCA, consisting of four 20 minute instructed sessions. It was cool out, and during the first 7 sessions (4 on Saturday and the first 3 on Sunday) the needle never moved off the 180 mark. This is with lots of WOT and speeds of 120+ MPH. I did two things though: I drove the whole track in 4th gear, except down the front straight when I went into 5th. During the braking I would go back to 4th. This was good and there was plenty of torque, and I was taking it easy, shifting into 5th at 100 MPH so I wasn't super high on the revs. I checked the coolant after each session and when I got home last night, it was right at the full mark every time, so I believe this issue is resolved.

On the last session on Sunday, I experimented with downshifting to 3rd in the braking zone leading into turn 4. This gave me a little (actually a lot) more torque and I was able to pop out of the corners especially out of turn 7 which is a 180 degree right turn that leads uphill. After turn 7 I would be back in 4th leading into 8/9 and then down the front straight and back to 5th. I was on it hard, and in this configuration the needle would go up to the 12:00 position and slightly beyond and touch into the 0 but it would start to go back down as I progressed down the front straight (that front straight is where I do most of my checking of the gauges). The only other time it went above the 180 mark was sitting on the grid waiting to go and there was an incident so we were stuck there for around 10 minutes. It crept above but as soon as we started moving it went right back down. I guess this is because there was no air going over the radiators and temps were too low for the fans to be on?

Fast lap of the weekend and this URL takes you to the videos for my final session, which was the most consistent and had my 3 fastest lap times of the weekend.

Track Attack

You can see where I caught up to a Cayman at the end of lap 5 and was stuck behind him until he finally let me around at the beginning of lap 8. I was stuck behind this same car during other sessions of the weekend. I guess I could charge up his tail a little harder but in the faster corners is where I could least afford to have to make a big change to deal with him suddenly slowing down. One thing I worked on during this session was backing off and trying to make a run up as I approached a passing zone.