EJ205 coolant leak

[gearnoob]

Hi All,

I'm a huge (gear)noob, and I just recently got a partially built 818C.
I've been trying to finish up the engine work, but I noticed that when I started it I ran into several issues.



With the MAF plugged in the engine doesn't want to idle. It starts and then the RPMs drop to 1k RPM and then drop and die.
With the MAF unplugged the engine jumps between 2-4k RPM constantly


Lots of white smoke coming from the engine and a bit coming through the exhaust. I haven't been able to keep the engine running long enough to properly warm up because of the idling issues and the amount of smoke coming being troubling . I haven't run a coolant pressure test to try and find the leak, but I went under the engine while it was running (and after) and saw a small amount of coolant leaking from the bottom of the black engine cover (which covers the tensioners and everything) near the oil filter side... I didn't see any coolant inside the oil but it was also probably not run long enough to ruin all of the oil if there was coolant in the oil... I (hopefully) don't think that the problem is a head gasket because when I ran a compression test the results were fairly good (I think...) -
140psi driver side front
140psi driver side rear
150 rear passenger side back
145 rear passenger front


Any help/suggestions would be appreciated! :) I re routed a few lines and hope that I didn't accidentally route one where it shouldn't be... I couldn't figure out how to route the coolant expansion tank so I put it off to the side until I could find a diagram to help

[gearnoob]

Sorry for the bad picture, it was really hard to get a good picture of the leak but this is the place I suspect it is coming from:124130

[Ajzride]

I have a video that shows most of the coolant/vacuum piped up, and then there are some responses on what is missing/wrong. Might help you some. Otherwise we will probably need some pics/video of how things are hooked up.

https://thefactoryfiveforum.com/showthread.php?31639-Aj-s-818S-in-Houston&p=378824&viewfull=1#post378824

[gearnoob]

This is awesome! I just watched it and now I see where I went wrong with the expansion tank, I was confused because I was assuming that expansion tank was intended for the whole system and not just to serve the turbo.

There's also a very weird setup with the coolant overflow in my system (a decent amount was unplugged so I wasn't sure where it was supposed to go originally) but there is a T setup with one routed all the way to the radiator to what I think is the overflow from the radiator, one going to the radiator out (big one on the non-pump side), and then one was open to which I was confused since I figured that'd need to go to the overflow tank... Is that correct or should it go somewhere else?
I wasn't sure if that was right or not or why that T even existed and wasn't just a direct route to the overflow tank...

[STiPWRD]

The expansion tank does indeed connect to the whole coolant system, not just the turbo. Think of the expansion tank as the highest point in the cooling system - the vapor is meant to collect at the very top and once it reaches a certain pressure (of the cap), it goes to the overflow reservoir. I can't remember where I got this picture but this is how to connect it:
124142
Port A collects the coolant coming from the turbo, B collects coolant from the top of the upper crossover pipe (Wayne's mod), and C goes to the overflow (recovery) tank.

[gearnoob]

Thank you!

Anyone have any suggestions on what to do about the coolant leak and location...? My first thought was that my engine is f****d, but the compression test looked perfectly fine when I ran it before so I don't suspect it's a blown head gasket but also why would coolant be coming from that place? There's shouldn't be coolant in there?

EDIT: or any suggestions on the idling issue would be great too :)

[sgarrett]

I found that my hose clamps were slightly leaking. It let a little coolant out and it would gather and then drip off of whatever point was the path of least resistant. I replaced all of the clamps with t-clamps to eliminate the leak. I would suggest looking very closely at the connection that is higher than the point where you see the drips.

[STiPWRD]

Idle issue - it's likely you have a vacuum leak somewhere in your intake system, or a loose hose that isn't plugged in. When the MAF is plugged in and engine running, the ECU is expecting the measured amount of air at the MAF. So if more air enters through a vacuum leak, it could cause the engine to run overly lean and die out. You could try pressurizing your intake system and listening for leaks.

Coolant issue - you may want to remove your timing belt cover to try and spot the leak. It could be a bad water pump seal or possible a bad head gasket. Keep in mind, the head gasket seals around the pistons but also around the outer edge of the engine - it could be that the outer seal failed. You could have good compression but a bad head gasket. Try using a combustion leak tool (UVIEW 560000 Combustion Leak Tester).
https://www.ebay.com/itm/UVIEW-Combustion-Leak-Tester-560000-NEW/332514304721?hash=item4d6b65a2d1:g:--kAAOSwM21dNDJa

[Kurk818]

Thank you!

Anyone have any suggestions on what to do about the coolant leak and location...? My first thought was that my engine is f****d, but the compression test looked perfectly fine when I ran it before so I don't suspect it's a blown head gasket but also why would coolant be coming from that place? There's shouldn't be coolant in there?

EDIT: or any suggestions on the idling issue would be great too :)

I had a very similar coolant leak in that same area. Turned out to be a tiny puncture within the oil cooler hose that connects the oil cooler to the hard line. I would suggest removal of that hose and a thorough inspection for any damage (pliers tend to be used for its removal and can easily cause a pin hole)