Hey boys,
Well I just removed the heater core from the old track car. Im running XP in autox next year and Im trying to get the 325 as light as possible, but I have a question. The three coolant hoses that run to the back of the heater core are now exposed, what should I do with these? I've read some threads dealing with the coolant feed line and the sender line being coupled together but what should I do with the third hose that was going to the heater core? I ordered the M50 block off plate from bimmerworld that blocks the feed line from the t-stat, will that do the job and I can get rid of all the other hoses? Im a bit confused, need some help guys!!
Thanks gents!
-Ryan
1993 325is racing car type thing....
You want to block off the port at the back of the head and connect the T-stat line to the radiator return line. Remove all other hoses.
When you say you bought a T-stat block off plate, are you sure you're not referring to the M50 coolant blockoff plate (http://store.bimmerworld.com/shared/...t=products.asp)? This is for the back of the head, not the T-stat.
Yeah this is what I've purchased and I now see what your talking about, it took a moment of stepping back and really looking at it. Whats the best fitting to use to couple the two hoses?
-Ryan
Here we go, mine looks like this...Thanks J!
So if I block off the hose with the red X, than where do I route the one with the blue X? I obviously remove the two with the green X's, I beleive.
-Ryan
Last edited by noodlexyz; 08-14-2009 at 09:50 PM. Reason: Automerged Doublepost
1993 325is racing car type thing....
This first picture is the "before" routing. You'll end up making a hose depicted by the red line. The black circles in the middle show the hoses you'll remove and reroute. The one at the back of the head is plugged with the BW plate. The junction in the middle will be modified. IIRC, I bought an additional OEM hose from RM European that is the return to the coolant tank hose. This hose has the correct metric inside diameter for the T-stat nipple and the inline connector at the three way. I used a piece of this new hose to come of the T-stat and run down to the existing coolant return hose connector.
This is what it should look like when done. You'll only have the hose coming out of the T-stat to the return hose to the coolant tank.
Ahh so the coolant return hose is the one that runs underneath the radiator into the bottom of the reservoir. This hose it t'd into the one running from the t'stat back to the firewall, correct? All I am doing is completing the circuit by routing them into each other.
-Ryan
Last edited by noodlexyz; 08-14-2009 at 10:49 PM.
1993 325is racing car type thing....
One more question, the coolant hose running to the throttle body, what to do with that? Just plug it?
-Ryan
1993 325is racing car type thing....
Yes.
I'm thinking about doing this also while in there. Does the block off plate from BW work well? I'm a bit afraid that it might start leaking nd I'm actually making more problems for myself. Also, what's the best way to block of the coolant from the head to the throttle body?
Thanks!
Anders Skandsen - http://www.skandsenmotorsport.com - NASA MA Spec3 2011 Champion & Rookie of the Year
The easiest way to block off the line coming from the head to the throttle body is with a bolt and crush washer. IIRC the bolt is M12x1.5...might be M14x1.5. Take the barb piece with you to the auto parts store. You can also get the adapter from The Racers Market and add a temp sensor for an aftermarket gauge.
http://www.racersmarket.net/index.ph...mart&Itemid=93
Anders Skandsen - http://www.skandsenmotorsport.com - NASA MA Spec3 2011 Champion & Rookie of the Year
Back when I was doing this I remember reading that some folks had overheating problems after connecting these two lines. I capped both lines (rear head outlet and throttle body outlet) and have had zero overheating problems on the track. Just something to consider.
So far I haven't had any cooling issues with the car, it runs great!
-Ryan
1993 325is racing car type thing....
As long as that hose from the back of the head connects into the T fitting, it'll return the water to the radiator. Where there has been discussion on problems is when you connect the hose from the back of the head to the hose running into the back of the T-stat. That will cause water to recirculate into the head without running back to the radiator.
The alternate method shown above will work fine, but leaves a couple of unnecesary hoses in play. Simpler is better. Block off the port at the back of the head and connect the T-stat hose to the radiator return using the existing inline coonector.
Agreed, it didn't make sense to run it back to the t-stat at all and Im not sure who suggested that. Like you said, hot water just gets recycled back to the head. Also, the fitting to connect the t-stat hose to the rad-return hose is 3/4 and its barbed on both ends. I got mine from Menards for $3.00 or something like that. Indoor plumbing department iirc, and use a couple of the hose clamps left over to tighten up the 3/4 fitting between the t-stat and rad-return lines.
-Ryan
1993 325is racing car type thing....
lems with the BW blockoff plate at the back of the head? Just some RTV sealant and bolt on?
My car is a racecar with no electric or clutch fan in the front. I'm a bit worried to get myself into more trouble than I'm saving.
Michael: are you running without the fans?
Anders Skandsen - http://www.skandsenmotorsport.com - NASA MA Spec3 2011 Champion & Rookie of the Year
Yeah, just some RVT sealant and the two bolts, get them really snug or it will leak! About the no fan issue...I personally would not run a BMW without some sort of fan. These cars are very well known for their cooling issues and I feel its better to be safe then be broke. A fan is a lot less than a new motor and it may save your butt if you do run into a cooling issue. Just my 2 two cents.
-Ryan
1993 325is racing car type thing....
I have a small 10" Jegs fan fastened to the front cross member in front of the radiator. It's hooked up to the stock wiring harness with an 80 degree switch. The fan rarely comes on, though. I have such good airflow that the car runs cool. If it's sitting at idle it will kick on, but if the car is even moving 5mph in the paddock it won't need to come on. You certainly don't need a fan for a car in motion as some think. But for a racecar, a fan is a good idea in case you're stuck on the grid or something.
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