Ok, long story short I noticed my Evo temp gauge starting to rise a few weeks ago, so I checked the coolant... it was very low. Filled it up. Now every time I drive the car I see it's leaking some but coming from the back of the block area. As you probably know, it's very difficult to see back there. I think I finally found where it's coming from but don't know what it is or why it's there. There's just like a hole back there that looks like it's missing its mating part...? If anyone has a picture of the back of an Evo VIII block that's outside the car, that would really help. It doesn't seem to be threaded and about the size of a quarter or half dollar.

This picture was taken looking down the back of the engine/ block, between the intake manifold; that pipe you see running horizontal-ish is the hard pipe for the water pump (I believe). So, what is this hole here for, is this the issue, and how do I fix it? I am really stumped on this... looks like there's supposed to be a cap there but what is the purpose?



PS - if it matters, 10 miles to work (~30mins city driving) leaves a puddle under the car about the size of a dinner plate. I can also see coolant on the trans-case.

 

Need a better pic. Hopefully it's not your headgasket(probably is)...

 

which runners are you taking the picture through?

 

I can't get a better pic; it's too tight. It took be five tries to get that one.

I don't think it's the hg. The car has ARP head-studs. I've been watching my oil like a hawk and it's not showing any signs of coolant. I've also let the car idle and held a piece of paper to the exhaust to see if it's spitting any liquids out, which it wasn't. I would think with a metal hg, when they break they break bad...?

Two and three, right in the middle...

 

Are there any guides online that show a detailed view/ schematic of the engine block? What goes where and such?

 

the "unthreaded hole" sounds looks like a freeze plug

 

the brass "caps" in the picture $2 part at napa 35mm freeze plug

 

It looks to be a freezeout plug. Bring it somewhere to replace it.

 

i know im no evo expert but damn its pretty obvious that the circle thing down there is a core (freeze) plug lol. if that coolant pipe is easy to take off then i would think that popping that old plug out, cleaning the sealing surface of the block and tapping a new one back one in there from the bottom side of the car shouldnt be to hard. but again im no evo expert and there is probably all kinds of stuff in the way under there huh. good luck sir.


mike

 

Ok, sounds like we're getting somewhere... so what happened, did the original one just pop out or something? Would one of those coming out cause a minor coolant leak?

Thanks,

 

no u can see it sitting in the hole still so its there its just leaking. these things happen.


mike

 

get something rubber to get in there with tap it around the ends and leak fixed. keep an eye on it till you replace it.

 

I doubt it's the freezeplug leaking.do you physically see coolant coming out of it? I actually just got done hunting a leak myself. I noticed there was some type of fluid by my shifter linkage so I removed the uicp to get a better look. Once I removed it I noticed a puddle of coolant on my transfer case. Spent about 30min looking for possible leaks. Found out the coolant line going from throttle body to back of head was leaking. There was a small slash on the bottom side of the hose that was leaking colant slowly. The line looked very brittle and must have cracked over the 5 years of me owning it. I was also losing coolant and could never figure out why. I would have to top off my radiator every week or so. Check those 2 lines that go to the TB..squeez the lines and see if any coolant comes out, that's what I did.

 

I did the same thing (popped the UICP off) and felt around all the rubber lines that came off the back of the motor where there'd be coolant coming from and they're all okay. Sometimes those little metal clamps will tear into one of those rubber hoses. I will try and squeeze them but I did feel all around them and didn't feel any cuts or coolant on the outside. But sounds like we have the same results because the back of my block and trans-case are both covered in coolant.

One of the problems in finding the source is the car only leaks it when I drive it/ under load. But, by the time I drive it to get it to leak enough, it's so damn hot under the hood it really limits my ability to search around. I wish I could just let the car idle and see if coolant is squirting from somewhere but it's not working that way.

 

Can't even see them from under the car. Transmission and x-fer case are in the way. Don't really want to have to take those out...

So one of these freeze pulgs becomes unsealed it would cause a coolant leak? Since it seems the bushing is still in there it makes me think that might not be the issue...

Anyway, what's the point of those things anyway? To aid in the expansion and contraction of the block as it heats and cools?