alright here it is... my first issue with my S. I took it to my dealer in Wilmington due to coolant loss and subsequent increase in engine temp. Related to this the heater pumps out cold air when I slow and stop. They decided that the coolant hose connected to my AEM intake was leaking and put on a new clamp. However I am still losing coolant and the engine runs hot as soon as I'm down 1/2" from the rad. fill cap (which is like every other day). The overflow is between min and max. I took it back today and am scheduled for a follow up tomorrow morning. A few of the mechanics were trying to assess what could be wrong and where the fluid is disappearing to. There is no evidence of any leak. I've looked all over the engine compartment and under the car every time it's parked. What I wanna know if anyone knows is how effective are the one way valves on the AEM intakes at stopping water from entering the manifold? There was some speculation from one of the mechanics that it may be the issue. The other speculation is that the head gasket is leaking. The head has considerable leakage on the VTEC side. What I'm afraid of is that they are going to blame whatever the problem is on my aftermarket cold air intake.
Tim I wanted to take it up to you at Scott but transportation is an issue since I live in Wilmington. Union Park so far seems like they're competent. I'll keep you posted but if anyone has any similar stories, outcomes or advice I'd appreciate it.
Brad

 

To the best of my knowledge, there are only two hoses that attach to the AEM CAI. Neither of these carry coolant. One takes intake air to the air pump behind your left fake air duct. The other one is the valve cover breather hose that shunts any escaped oil vapors back into the intake for combustion.
When the AEM is installed, the tubing loom is removed and all water lines are replaced with longer ones that is supplied by AEM. If one of these are leaking, you will see blotches of dried green coolant under those connections.
You say that your rad level is down 1/2" below the rad cap and you also say that the coolant tank is between min and max. I cannot see this as being possible. If you are down that far in the rad, your coolant tank should be pretty much empty. It seems to me that you have not got a solid, tight connection between the rad spout overflow pipe and your overflow tank. Check to make sure that the little spout pipe is not cracked, the tubing over that little pipe is not loose and that the other end of that tubing is secure. If this is not the case, then when your engine heats up, it will blow the expansion out and onto the rad, where it will dribble down the rad fins and get evaporated off. It would be hard to see any fluid then. You can pull off the tubing from the rad cap area and easily lift out the coolant tank for inspection. If the tubing was too easy to pull off, you may have found your leak, OR, if the pipe that the tubing came off of is not solid, there may be a break in it.
Also, have you checked the viability of the rad cap itself?
These are easy checks to make. It may not be this in your case, but you should at least eliminate them first before having nightmares about head gaskets, which BTW, should give you a white steamy exhaust.

 

Actually, I have the same issue since I installed my Injen. When you replace the stock intake hoses, there is a coolant hose that I replaced (and quite a few people do). The problem truly is that the coolant hose you (and I) replaced with is a drop too big.

There is a post in Under_The_Hood that Xviper originally did about CAI installs and I added in what seems to be the correct hose sizes.

excerpt from the post
I but my hoses from www.overboost.com Injen dressup kit, but only when they're on sale.


I haven't replaced the coolant hose with a newer smaller one yet, just added two clamps which I occassionally tighten but I'll get around to it one day.

Here is a pic of my engine, look at the garden hose looking hose (home depot style). Mine leaks on the side closer to the engine (and creates a coolant smell).

 

Brad from my knowledge I don't see how the AEM would be the problem. I would ask them to do a compression and leakdown test. This will help to determine if you have a blown or leaky headgasket. As soon as I read the symptoms that is the first thing I thought of. Do you have any type of smoke at idle or while driving?

 

Nate I haven't noticed any noticeable smoke coming from the exhaust. I blew the head gasket in my dad's old 300Z and that was like an arcade game with billows of white smoke coming from the exhaust. The tube from the coolant to the AEM is secure. They are going to do a compression/leakdown test tomorrow. One guy there tried to say that water may have gotten into the manifold from the AEM but I have that water sleeve inserted which in my estimation is near impossible for water to ever get through unless i submerge the intake filter (which I havent). We'll see. I inspected the resevoir and tubing which all seems adequate and intact. From what I understand if the coolant level is low in the rad. it can inhibit the vacuum created as the engine cools and sucks coolant in from the resevoir... which appears to be happening. The compression test should give some clue or at least rule out a big job that hopefully will be covered under warranty. The rad cap itself shows no signs of leakage and trust me... ive been inspecting it twice a day and all the undercarriage for any signs of green stuff. My car is a '02 so I think I have grounds for a good arguement no matter what the problem is. Thanks for the responses... I'll keep ya'll posted!!!

 

Alright well their findings concluded nothing other then that the gasket/O-ring sealing the VTEC solenoid was bad which was why oil was leaking onto the head. The pressure tested the system which was without a problem. They did notice that there was air in the system by the heater core which could have caused the car to overheat but doesnt account for the coolant loss. The possiblity that was posed was that a cylinder may be cracked which would cause fluid to enter into combustion and burn off. Apparantly there is a test for that too which they said was done... testing the coolant for exhaust gas. again... nuthin...I have to take it back on Monday for the O ring which should give me enough time to see if I continue to loose coolant.

 

I doubt its a cracked sleeve. Everyone that I know that cracked a sleeve had crazy smoke problems and their car wouldn't run, so I doubt its that.

 

ok well ... phew! That was my main worry. Let me tell ya this though... when I start my car after it's been sitting (maybe im being paranoid)... it idles rough for about 10 seconds... i never noticed it before but then again i never paid attention to the sounds it makes this much before either...? so far... no coolant drops... no temperature spike.