Wasser Pumpen!! (and thermostat)

ThunderChicken

ThunderChicken

2
#1
Messages
34
Likes
0
Location
North Carolina
#1
Does anyone know exactly what happens when a water pump 'goes out'? Is it usually just the gasket or is it massive corrosion? it seems too simple of a design to actually 'go out' the way finicky electronics could.

back story: I was having overheating problems, which turned out to be a stuck thermostat. then when i went to inspect/replace it, i discovered the one i had in the car did NOT match my replacement (which matched the one in the haynes manual). It was made in france! so my first thought is, 'ah ha! the frogs have sabotaged my car!' but then it turned out my replacement didn't even fit inside the thermo housing. Perhaps, if i filed the edges a bit it would, but the thermostat seemed fine, so after a little wd40 and wire-brush action, i put it back in. now, all works fine!

except....now my idle is crappy. WTF?!?
 
selavia

selavia

2
#2
Messages
1,035
Likes
5
Location
Maryland
#2
Personally, I wouldn't go by the haynes manual; check with a BMW parts list or the Bentley manual.

I do not kno what's causing the crappy idle. What did you wire brush? The thermostat? I really think you may need to get the proper thermostat. Take the one that was in your car prior and match what you know works, not what the manual says. Just a suggestion.

I used a haynes manual for a Toyota and it has 'recommended' incorrect parts.
 
ThunderChicken

ThunderChicken

2
#3
Messages
34
Likes
0
Location
North Carolina
#3
yeah, what i meant by 'wire brushed' is i just cleaned off the one i took out, and put it back in. seems to work fine. except for the aforementioned idle thingy.....
i'm thinking it's either a small air leak, or the cold start thing operating when at normal temp. any tips on fixing that??

engine runs fine when throttled, but sputters a bit when stopped. argh.
 
selavia

selavia

2
#4
Messages
1,035
Likes
5
Location
Maryland
#4
For small air leak, check the MAF boot... mine had a crack in it after 130k miles. Check all other hoses; a little soapy water in a spray bottle usually is a good way to find leaks.


If the problem wasn't occuring before fiddling with the Thermo, you may still need to replace it. It would probably be a good idea to replace the thing. The dealer (at least in MD) is very reasonable for parts.
 
Doughnut

Doughnut

2
#5
Messages
984
Likes
1
Location
Australia
#5
When you "wire brushed" you more than likely scratched the TEMPERATURE-TIME SWITCH, which plays a big part in idle control, i wouldent go replacing it without knowing that was the problem though, the new part from bmw is quite expensive :(
 
jrt67ss350

jrt67ss350

2
#6
Messages
1,831
Likes
0
Location
Winston Salem, NC
#6
The thermo-time switch only operates the cold start injector. It doesn't have anything to do with the idle specifically. I doubt that is the problem.

I've got my money on an air intake leak like Sean alluded to. Check and make sure all of your clamps are tight on the air intake bellows and go over the air intake bellows/boot with a very critical eye - if you have cracks in it, that can cause your problem, and it needs to be replaced.

Also just make sure that all of your wiring connections at the mess of coolant temperature sensors in the thermostat housing are secure and tight.

Can you be more specific about how your idle is crappy?
 
ThunderChicken

ThunderChicken

2
#7
Messages
34
Likes
0
Location
North Carolina
#7
when it was idling smoothly before, it was at a solid 750 rpms. now it wavers around 525 to 600. it'll go to 600, and then start dropping off like its about sputter out. then it kicks back up and repeats. it does this twice a second, roughly.

i'm thinking air leak, but could somebody elaborate more on the thermo time switch? which wires are those, and also, if that kept the cold start injector active at normal temps, could that be the issue?
 
jrt67ss350

jrt67ss350

2
#8
Messages
1,831
Likes
0
Location
Winston Salem, NC
#8
Sounds like it's most likely an air leak to me.

This is the thermo time switch:

It should have a unified plug on it, so it's doubtful that the wires are loose.

An easy way to test it is to unplug the wiring connector from the cold start injector - if this fixes your idle problem, then it is likely the thermo time switch.

The other thing it could be is the coolant temperature switch for the idle computer. This is a yellow-topped switch on the thermostat housing that connects to the wiring harness with two spade connectors. Wiggle those connectors and see if the idle improves.

Where in NC are you?
 
ThunderChicken

ThunderChicken

2
#9
Messages
34
Likes
0
Location
North Carolina
#9
Hey, I got it! Fortunately, nothing complicated or expensive.

I started poking around under the hood yesterday with the engine running, and just started wiggling everything i could find to see if it changed the idle, and when i lifted the air flow sensor......the idle went steady! There was a minor crack underneath, whatever hose thing goes into the throttle body. Why are the cracks always on the bottom?! Anyway, can't get a new hose until next week so........DUCT TAPE!

and now, all is well!

thanks for all the input though, the more i know about how all this stuff works, the better.

cheers!

oh, and I'm in Hubert (between Jacksoville and Swansboro)
 
You must log in or register to reply here.


Top