Hello All,

I'm currently trying to help out a friend who owns an Evo7. The current issue is, is that his water pump inlet is now chocolate pudding (rusted out) along with the thermostat housing. I've done my research and here are my findings.

1. Evo 4 - Evo 7 can all use the same water pump. Part Number(s): MD977311 MD978552 MD975913 MD975644 1300A069
2. Evo 4 - Evo 9 (skipping the Evo 8) can all use the same thermostat. Part Number: MD363571
3. Evo 8 does not have a bypass, hence the reason there thermostat is different. Part Number: MN143463
4. Evo 7, 8 & 9 all have the same thermostat gasket = same bolt pattern. Part Number: MD363254
5. All Evo's from 1-9 use the same water pump o-ring. Part Number: MD030764
6. Evo 7 and Evo 9 use the same mini bypass o-ring. Part Number: MD030763
7. Evo 4, 5, & 6 Radiators can be used in the 7, 8 & 9 with using the top radiator house from the Evo 4, 5 or 6 which gives a lot more clearance when running tubular manifolds.
8. The Evo 8’s lower radiator hose is the longest out of the Evo 8 & 9.

So, the Evo 4 - Evo 7 all use the same water pump but have different water pump inlet designs. Evo 4, 5 & 6 have a similar set up. For a fact the Evo 8 has a different set up on its own, and does not have a bypass. The Evo 7 & 9 have a similar set up with the bypass coming off of the water pump inlet into the thermostat housing. The Evo 7 & 9 water pump inlet are both similar in design with the Evo 9's having a more steeper bend.

With that said, I'm thinking that if I purchase the Evo 9 water pump inlet along with the Evo 9 thermostat housing it might actually work on the Evo 7.

If anyone has done this before please confirm this can be done? It would be awesome to know if this could work.

Kind Regards,

Sumo

I do not believe the water pump is the same, correct me if I'm wrong but the Evo 7 uses a bigger water pump then the 8 & 9 do. Where the 8 & 9 have one flow path into the block from the pump, the Evo 7 has two which requires a bigger pump to cover both orifices.

For this block you will need to use the water pump and pipe from a 2003 Mitsubishi Outlander.

some wrong info there
4/5 use same piping and stat housing and stat
4 to 7 all same water pump

6/7/9 use same piping stat housing and stat

8s different pump pipe stat housing and pipe in the head

so yes you can use the 9 steel pipe on the 7 stat housing

From what I see the Evo 8 is in a world of it's own lol. The only parts that are interchangeable are the o-ring and gasket. If you can, could you provide a part number? Engine size and model would be good as well.

Thanks for the corrections

Not in anyway saying you don't know your stuff, but could you give me a little more hard evidence. This is a learning process for me, and I'm doing this job for a friend. I wouldn't want to be spending his money on parts only to find out it doesn't 100% work. The biggest issue is finding the correct part number to cross reference.

I can tell you one thing! Whenever I do this job, and if it is with Evo 9 parts I'll definitely be taking pics. . It will definitely kill two birds with one stone, if Evo 7 owners just have to buy the Evo 9 wp inlet and t-stat housing and go. The biggest hurdle is that the search for Japanese parts can be ridiculous at times.

I was running a 9 mivec eng in my 5 , 9 water pump ,7 steel pipe and 6 stat housing and stat .


pipe md375781
stat md363571
housing md363250
cover md363251

pump md977311 (4 to 7)

That's all I needed man. Thanks again! I just actually ordered the pipe, o-rings and gasket. Then I logged on only to see your reply

Pictures coming soon

Just a small update. Yesterday I installed the Evo 9 water pump inlet and thermostat. changed the o-rings and secured everything back to its original position. As for the inlet, it's a direct fit.

I just ordered a few additional items that are needed to finish off the work.

Here's a teaser pic

Hello All,

Below are the water system parts that are interchangeable and that aren’t between the Evo 4 – Evo 9. I've done my research and here are my findings along with corrections.

1. Evo 4 - Evo 7 can all use the same water pump. Part Number(s): MD977311 / MD978552 / MD975913 MD975644 1300A069

2. Evo 6/7 can use the Evo 9 water pump inlet. Part Number: MD375781
3. Evo 4 - Evo 9 (skipping the Evo 8) can all use the same thermostat. Part Number: MD363571
4. Evo 8 does not have a bypass, hence the reason there thermostat is different. Part Number: MN143463
5. Evo 6 - 9 have the same thermostat housing gasket = same bolt pattern. Part Number: MD363254
6. Evo 6 - 9 have the same thermostat cover. Part Number: MD363251
7. Evo 6 - 9 have the same thermostat housing. Part Number: MD363250
8. All Evo's from 1-9 use the same water pump inlet o-ring. Part Number: MD030764
9. Evo 6/7/9 uses the same mini bypass o-ring. Part Number: MD030763
10. Evo 4/5/6 Radiators can be used in the 7/8/9 with the use of the top radiator hose from the Evo 4/5/6 which gives a lot more clearance when running tubular manifolds.

11. The Evo 8’s lower radiator hose is the longest out of the Evo 8 & 9. This can also be used on the 7/8/9 with some minor cutting involved.

The Evo 6/7/9 all use the same water pump and have similar water pump inlet designs, keeping in mind the Evo 9’s water pipe has a deeper bend to clear the last two intake manifold runners, I’m not sure that the Evo 9 can use the Evo 6 & 7 wp inlets. The Evo 6/7/9 have a very similar set up with the bypass coming off of the water pump inlet into the thermostat housing. The Evo 8 has a different set up on its own, and does not have a bypass.

When It comes to the Evo 4/5, they have the same thermostat housings which differ from the Evo 6/7/8/9. The also use two o-rings instead of one.
A big THANKS goes out to todd6027 and his valuable information. I’ll update with some Evo 4 & 5 part numbers in the future.

Kind Regards,

Sumo

Last Edited: Dec 15, 2014