I got stuck in rush hour traffic of friday on my way home from work. I was on the phone with my boss when I heard a loud pop behind the dash which was instantly followed by scorching hot steam coming out of every vent in the cabin resulting in 2nd degree burns to the top of my right foot and left ankle.
I shut the car off, coasted to the shoulder and got out to look. Coolant was pouring underneith, right above the trans. Popped the hood but everything was dry up front and on the firewall. Crawled under the car to take a look and it looks like its coming out of the cabin
Symptoms:
Steam out the vents
Soaked carpet
Coolant leaking above trans
Dry firewall
Conclusion:
Something exploded in the heater core
Ive been doing a lot of searching today to figure out how to bypass the heater core, but I need a little more clarificaition.
My understanding from the track guys is this:
Block off coolant passage on rear of the head using DIY block off plate or one purchased from BW
Splice the forward section of the spider hose into the return hose of the expansion tank thus eliminationg the spider hose completely and routing the coolant back into the system to go through the radiator. I also saw someone suggest using a single hose from the front motor coolant passage directly to the expansion tank but I didnt see anything else about others who have done this.
This method involves removing the intake manifold to gain access to the coolant hoses underneath and the coolant port at the rear of the head. What I’m looking for is a quicker fix that will just temporarily bypass the heater core until I have enough time to tackle the heater core replacement.
This is my thinking:
The heater control valves have 3 hoses running into them. One is the feed from the rear of the head, the other two go into the firewall for the independent climate zones. If I loop the two going into the firewall, no coolant will go to the heater core, and down the line I can just pull the loop off and reattach the stock hoses once I replace the heater core.
Anyone familiar enough with the e36 chassis to know if this will work? Are there issues with looping the ports coming out of the heater control valves?
I can’t say I know what you are speaking of with 3 tubes etc. because I do not know these cars well, but for a lot of customers when I used to work at quick lubes, if their heater core was plugged, I just took the two hoses going in and out, joined them with a piece of copper tubing, and two hose clamps. They were ice boxes but no more plugged overheating issues
Can you post photos of the lines going into the firewall?
Hose running along the bottom to the valves is the supply from the rear of the head. Two hoses visible going to the fire wall are the supply to the heater core (ones I intend to loop). 3rd hose coming from the firewall I think is the return. This picture has the manifold removed which allows easy access to everything. With the manifold on, it’s a very tight squeeze getting to the two hoses on the valves and nearly impossible to access the hoses on the firewall.
If I just loop the valves to close off the supply, what will happen with the return coming from the firewall? Doesn’t that need to be spliced into another line in the system so the system can be pressurized?
Jam, it has dual climate controls so on the firewall one hose is DS, other is PS, and the one furthest to the left is the return from the core. I think I’m going to try pulling the supply and return and plug each end. Bimmerforum members are adamant about NOT connecting the two together so plugs it is.
I have done both options. Looped and plugged. My gtr is looped my chevy celebrity was plugged. My GTR does tend to run on the “cool” side. (Oil temp 220, coolant temp 150)
Does the hose that looks like it’s heading L to R under the 3 firewall hoses feed the two valves? If so, either loop that to the return or plug them both…
Yes. Comes off the rear of the head. Planning on plugging it.
Need to be able to drive the car until I have the time to tackle the heater core removal/installation. Not an easy task to say the least. And I have a month or two before it gets cold down here
It was highly suggested to NOT do this as it somehow affects the cooling at the rear of the head. I’m just gonna try to plug them without removing the intake manifold :fingerscrossed:
I wouldn’t loop the hose…if you loop, coolant from the back of the cylinder head is unable to be cycled back into the radiator and sending hot coolant back into your cylinder head. It might just be easier changing the heater core vs. blocking the cylinder head & pluging the hose properly.
I ended up getting 2 plugs at Lowes from the plumbing section. Bought 2 brass and 2 PVC but the brass ended up being a little to small; no resistance when put it in the end of the hose, so PVC it it is. I only removed the elbow off the throttle body along with the MAF. That gave me enough room to snake my hand under the manifold and reach the hoses. I used a long flat head screw driver and was able to loosen the clamps on the firewall and the control valves from the topside and grabbed the hoses with my other hand to pull them off under the manifold. Both lines were plugged in ~30 mins.
Fix was short lived. Drove to work at 6pm last night and got home around 4am. Went back out to the car around 6am and then went to bed. Was woken up at 8:30 by 2 officers and a fire marshal asking if I drove a black BMW. This is what I walked out the door and found:
