[AlanH]

Hi all,

So my thermostat has been diagnosed with being the cause of my Service Engine Soon light. I brought it into to get it repaired today, but some people suggest to get the waterpump replaced at the same time. However, my water pump is not the reason why the car is shooting out the code, and my car is sitting at 66k miles at the moment.

Dear owners, would you recommend getting the water pump changed as well? Right now I'm quoted around $400 to fix the thermostat, and around $1000 to do the whole thing.

[Fortyb]

Change it all.. And save yourself some money and do it yourself..If you know how to turn a wrench.

[Blackhawk36]

$1,000 is a great price for water pump and thermostat on a 335i. I assume it includes new coolant.

You should do it. With a 2007 335i your pump could go out anytime in the next 130,000 miles but will probably go out withing 5,000 or getting your thermostat replaced.

I just did mine at 100k and it was working perfectly. I was just tired of toying with the BMW water pump gods.

[m@rco]

What's the cost for a waterpump replacement only? Ask for a quote on paper so you can refer to that in the future. If it is significantly more than the difference, yes. If not, then keep driving. Do you live far from the dealership? If so, spare you the time and get it done now. Do you plan to keep the car for a while? If so, better enjoy the investment now. If you plan to sell it in the next 30k miles, leave it, you might be lucky...

[Nguyenhu0106]

Originally Posted by AlanH

Hi all,

So my thermostat has been diagnosed with being the cause of my Service Engine Soon light. I brought it into to get it repaired today, but some people suggest to get the waterpump replaced at the same time. However, my water pump is not the reason why the car is shooting out the code, and my car is sitting at 66k miles at the moment.

Dear owners, would you recommend getting the water pump changed as well? Right now I'm quoted around $400 to fix the thermostat, and around $1000 to do the whole thing.

it's all the same work.. and would be cheaper in the long run to get it changed all at once... these WP are tricky anyhow.. it could go out at anytime and there is no min or max mileage to it.

[AlanH]

I know the nephew of the owner of the shop, but the shop itself is around 10 miles away. I think it would cost another $800 to fix the waterpump by itself.

Essentially, I'm gambling an extra $200 on the next 5k-10k miles. Which is probably around another year for me.

@Fortyb I don't trust my own mechanical skills. With a car like this, I would rather not do my own work on the engine. (First big investment post-college)

[hockeyplayer]

OP go ahead & do it. You'll likely be replacing that water pump within the next 30K miles anyway.

[WRichieX]

My tstat was throwing a code too so was planning on just doing the t stat myself and not the water pump but everyone does say just do it together since they are both together and pump will go out sooner or later. However, after a couple month of driving, the t stat code went away and I'm on day 5 with no code and oil temp warms up quickly. Not sure what's going on. I have the t stat ready to install but might just wait till the pump starts to fail and do it all together

[m@rco]

Originally Posted by AlanH

I know the nephew of the owner of the shop, but the shop itself is around 10 miles away. I think it would cost another $800 to fix the waterpump by itself.

Essentially, I'm gambling an extra $200 on the next 5k-10k miles. Which is probably around another year for me.

@Fortyb I don't trust my own mechanical skills. With a car like this, I would rather not do my own work on the engine. (First big investment post-college)

Difficult. I understand the others' suggestions to get it done now. But, yeah, not cheap... And you don't drive too many miles. If you drive, do you drive long distances? In other words, does your engine reach operating temperatures and operates at constant temperatures? Or do you do many short trips, with stop-and-go traffic and thus different operating temperatures? On the one hand, in the latter case, the chance of a failure is higher. On the other hand, if you drive long distances the pump operates at constant temperatures. Thus, there is less chance of a failure. But IF it happens during a long distance trip, you're not a happy camper either...

[AlanH]

Originally Posted by m@rco

Difficult. I understand the others' suggestions to get it done now. But, yeah, not cheap... And you don't drive too many miles. If you drive, do you drive long distances? In other words, does your engine reach operating temperatures and operates at constant temperatures? Or do you do many short trips, with stop-and-go traffic and thus different operating temperatures? On the one hand, in the latter case, the chance of a failure is higher. On the other hand, if you drive long distances the pump operates at constant temperatures. Thus, there is less chance of a failure. But IF it happens during a long distance trip, you're not a happy camper either...

My most common drives are short distances, (10-20 miles) and Bay Area traffic has a lot of stop-and-go traffic.

[Andrewah05]

Change them together, will save you the hassle for going through the process again, not sure if just because the thermostat failed the pump will eventually fail, but its good measure to do both, did the thermostat failure leave you stranded? Because I know if the water pump fails it will.

[Eddien123]

If you don't replace it now. You'll be taking it back very soon to get it changed. I recommend getting it done now. And I also recommend doing it yourself to save some cash but that's your call.

[Blackhawk36]

Originally Posted by AlanH

My most common drives are short distances, (10-20 miles) and Bay Area traffic has a lot of stop-and-go traffic.

When the pump quits, it is usually quick. Your radiator fan will go on full blast then about 10 seconds later you will get the yellow over temp light, then about 20 seconds later you will get the red over temp and go into limp mode. In heavy traffic you will be stuck where you are. That will suck for you and all of those other commuting Schlubs. You will not make any friends.

[zuti]

Our thermostat went out two years ago at about $300. A month later the water pump went, about $600. Do them both together and save your time, which is worht something. I'm a gear head, but my understanding is that the thermostat and waterpump are electronic (really? What's wrong with the good old $5 thermostat and $80 belt driven water pump - Oh well). I suggest you do both at once! Zuti

[Efthreeoh]

I disagree about changing the water pump if only the t-stat needs replacement. It is not the same labor cost to replace both the t-stat and water pump if only the t-stat is bad. The t-stat is an $80 part and comes off without removing the water pump. The water pump is a $400 part and requires removal of the t-stat, which is why you DO save labor replacing the t-stat when the water pump is bad. The water pump usually throws codes that do not trigger the SES light, but are recorded in the ECU and readable with a BMW scan tool. There is no set mileage when the pump may go, so replacing it preemptively is a crap shoot IMO.

I would have the car scanned first to see if the pump has been throwing codes before I replace it.

[GoRomeo]

Originally Posted by Efthreeoh

I disagree about changing the water pump if only the t-stat needs replacement. It is not the same labor cost to replace both the t-stat and water pump if only the t-stat is bad. The t-stat is an $80 part and comes off without removing the water pump. The water pump is a $400 part and requires removal of the t-stat, which is why you DO save labor replacing the t-stat when the water pump is bad. The water pump usually throws codes that do not trigger the SES light, but are recorded in the ECU and readable with a BMW scan tool. There is no set mileage when the pump may go, so replacing it preemptively is a crap shoot IMO.

I would have the car scanned first to see if the pump has been throwing codes before I replace it.

This. . .