MECS Pump Replacement

  #11  
Old 07-28-2009, 08:36 AM
Ridiculously Active Enthusiast
Thread Starter
Join Date: Jan 2009
Posts: 863
Default Re: MECS Pump Replacement

There's a vent plug for MECS system high point inside the transaxle cooler.

Since you end up draining the system when you replace the pump you end up using the system fill procedure by the manual.

It tells you to loosen (I ended up removing it) the transaxle vent plug when filling. It says to fill the system until coolant comes out the vent plug hole then to tighten it (don't overtighten it, it has a rubber o-ring on the plug and you can crush that causing a leak) and then to finish filling the MECS system.

This plug is on the back (sloping & toward the firewall) side of the transaxle underneath several cable plugs going into the transaxle. It's not hard to get to, but you'll have to poke around with a flashlight to see it the first time

It takes a 12mm socket and if you remove it instead of just loosening it, you'll end up disconnecting a multi-pin electrical plug just above it to get a straight shot on the hex to re-install it.

Disconnecting & reconnecting this plug was no big deal for me. If you just loosen it, as the manual says to, you might want to use a u-joint for the socket. You'll need no more than a 1/4" drive socket.

Since the system is self venting it tells you to check the expansion tank as you run the engine to ensure it is topped up. But I did not have to add coolant after refilling it.

Remember the pump comes on when you go to the run position (KOEO) whether you start the ICE or not, this is because the HV Electrical system comes on then. You can use this for the first check of level.

I suspect that if you did not vent the transaxle you might have to add a pint or so. The air bubble in the transaxle internal cooler may be sizable.

I don't think you would get a trapped bubble here since the pump is a pressure source that can sweep any bubble out of the cooler. But you will see a drop in expansion tank level accordingly if you don't vent.
 
  #12  
Old 07-28-2009, 08:41 AM
Ridiculously Active Enthusiast
Thread Starter
Join Date: Jan 2009
Posts: 863
Default Re: MECS Pump Replacement

The pump I received was listed as an 08 pump. Do not know whether the 08s have the same problem as the earlier ones. Just have to watch as these roll up on 50k.

One quick check you could do is look at the pump and see if it is a Bosch unit. If it is I suspect you'll have the same problem. Its about 6-8 inches long. The replacement pump is about 2-3 inches long, and much smaller.
 
  #13  
Old 07-29-2009, 08:39 PM
TriggerHybrid's Avatar
Enthusiast
Join Date: Jun 2007
Location: Las Vegas, NV
Posts: 39
Default Re: MECS Pump Replacement

Thanks for the info above Bill, Nice post that I'll bookmark for later usage.
 
  #14  
Old 07-31-2009, 06:40 PM
Ridiculously Active Enthusiast
Join Date: Nov 2006
Location: Southwestern Pa
Posts: 1,747
Default Re: MECS Pump Replacement

A photos is worth a thousand words:
Name:  MECSPUMPFAILAT50KLargee-mailview.jpg
Views: 1462
Size:  159.2 KB
 
  #15  
Old 07-31-2009, 07:33 PM
Enthusiast
Join Date: Jul 2009
Location: Colorado
Posts: 31
Default Re: MECS Pump Replacement

Being the non-mechanic that I am, I wondered what MECS was?

Then I Googled it, and it's the "Motor Electronics Cooling Pump"

Hope this helps others like me who don't know all the jargon.
 
  #16  
Old 08-01-2009, 10:48 AM
Ridiculously Active Enthusiast
Thread Starter
Join Date: Jan 2009
Posts: 863
Default Re: MECS Pump Replacement

Don't know what you're pointing at in your photo (kind of looks like the A/C receiver/dryer) but it's not the MECS pump.

The MECS pump is located down in front of & underneath of the engine next to the oil filter.
 
  #17  
Old 08-01-2009, 01:09 PM
Ridiculously Active Enthusiast
Join Date: Nov 2006
Location: Southwestern Pa
Posts: 1,747
Default Re: MECS Pump Replacement

I did goof and pointed to the wrong item. They say a photo is worth a thousand words.
 
  #18  
Old 08-01-2009, 01:27 PM
Ridiculously Active Enthusiast
Join Date: Mar 2006
Location: Ventura, CA
Posts: 887
Default Re: MECS Pump Replacement

Originally Posted by Billyk View Post
I did goof and pointed to the wrong item. They say a photo is worth a thousand words.
Darn! I just replaced that thing you were pointing to.
 
  #19  
Old 08-01-2009, 08:01 PM
Ridiculously Active Enthusiast
Thread Starter
Join Date: Jan 2009
Posts: 863
Default Re: MECS Pump Replacement

Been there, done that, still living so far.

What I want to know, econoline, is how you got the pipes to mate up and without leaks?
 
  #20  
Old 08-01-2009, 08:59 PM
Ridiculously Active Enthusiast
Join Date: Mar 2006
Location: Ventura, CA
Posts: 887
Default Re: MECS Pump Replacement

Originally Posted by Bill Winney View Post
Been there, done that, still living so far.

What I want to know, econoline, is how you got the pipes to mate up and without leaks?
PVC sprinkler fittings and duct tape. Just kidding of course, but I will take your advice and replace the MECS pump when I approach 50k miles. Did you mention a recommended place to buy the pump?
 

Thread Tools
Search this Thread
Quick Reply: MECS Pump Replacement


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.