mahunt

After an all too brief time in my car, the LASO replacement water pump for my M120 V12 engine has expired.

My original water pump lasted from 1997 until Feb 2018 (say 250K miles). The LASO pump I got from AutohausAZ only made it just under 4 years and maybe 15K miles. AutohausAZ warrantees the pump for 3 years, so I was in the market for both a better warrantee and longer lasting pump.

FCP Euro offers lifetime warrantee on their parts, so I decided to give them a call to ask about the warrantee and find out what makes of water pumps they offer. FCP doesn't list a phone number on their website, but a short web search revealed it as (860) 388-9001. Unfortunately, you get a voice message saying they are at lunch and to call back later. There is no option to leave a callback message or any message. Too bad, because I like dealing with FCP.

Inexpensive M120 water pumps are available on eBay, but are of Oriental construction. I expect the water pump on an all aluminum engine to be beyond question, and I'm not willing to roll the dice on such an important component. I ordered a new pump online from a local auto parts store (Advance Auto) and couldn't determine the country of manufacture from the online listing. The part showed up and sure enough it was, Hecho in China. Back it went for a refund.

As a last resort, I called the dealership and asked about their MB pumps. They only have rebuilt pumps (the pump bearing was from Italy), but they use OEM castings and come with a 2 year warrantee. I thought having a potentially better water pump was better than a poor quality pump, but with a longer warrantee. The dealership discounted the pump (I'm such a great customer) enough to make it comparable to what FCP and Advance Auto Parts was charging. So I ordered one.

The new pump showed up one day later and all they wanted besides my money was the old LASO core; for $75 they were welcome to it.

I'll get into the LASO pump failure and replacement in the next post.

AndreasHannover

Is Meyle available in the US? Typ 0130260016

mahunt

I didn't know Meyle made anything other than suspension components. I did check the number you provided and the websites that carry the part end in .uk, .ru, .ua, etc.

About 3 weeks ago I noticed that my serpentine belt was showing some cracks. No chunks were missing, but it was time for a new belt. I already ordered the replacement belt (Continental) and went about replacing the belt. After removing the belt, I checked the operation of each pulley for rotational smoothness and noise. In 2018 I replaced the tensioner pulley bearing and the idler bearing and they were still rotating quietly.

Only as an afterthought, I jiggled the water pump fan pulley and the water pump pulley itself. The water pump pulley flopped about an eight of an inch. Time to replace the water pump again after less than 20K miles.

When I originally got the LASO in 2018, I thought I read that they were the OEM supplier for the water pump and felt pretty good about ordering one. In truth, it didn't exactly fit as well as the original. The fit issue showed up where the coolant crossflow between the cylinder banks mates with the top of the pump. In other words, the thermostat housing. There is an O-ring at the top of the pump that is supposed to seal against the bottom of the thermostat housing and the 4 bolts that secure the thermostat, clamp everything together.

It took about 2 weeks of checking the thermostat housing for leaks (seeps really) and extra tightening before it stopped leaving white coolant residue trails.

The rebuilt pump from the dealership didn't have LASO cast in the face of the pump, just a few numbers. The fit, however, was spot on. When assembled, I could tell that the thermostat housing actually pressed down on the top of the water pump and all the bolt holes in the thermostat housing matched up perfectly to the water pump. This was also a problem with the LASO pump.

I had to wait about a week for the Advance Auto Parts pump to arrive, so I put the time to good use and cleaned the front of the engine (not that it was that soiled).

Here's the left side of the engine with it's new secondary air pump and the idler pulley removed for detailing.



Here's the right side of the engine. This photo and the one above it show the crossover thermostat housing removed as well as the water pump.



This photo shows the new water pump installed and the top of the pump where it mates with the bottom of the thermostat housing. A O-ring goes in the cavity before reassembly.



This experience has led me to checking the condition of the water pump pulley every so often to make sure it doesn't wobble.