Potential Radiator Enhancements

[m3f_HoonCrepe]

Hello all,



I have a 1999 e36 M3. The previous owner performed various cooling upgrades which included replacing the stock radiator with an aftermarket aluminum radiator. I have had several issues with this radiator. When I bought the car the previous owner had also taken the fan off as well. I sit in traffic sometimes and I didn't want the car to overheat so I installed a new fan. I had to pull the fan shroud out a little bit to help fit the fan and so I had to disconnect the hoses on the top of the radiator to create more room to get a wrench in there as well.



I discovered as I was assembling the hoses back on the radiator that the outlet to the engine and the outlet to the overflow tank are so close together that I cannot fit both hoses on with hose clamps. The hose clamp for the outlet to the engine is essentially sitting on the flange that is was supposed to sit in front of if that makes sense. This is because there is not enough room between the 2 outlets for both hoses and both hose clamps.



Eventually I developed a small leak on the outlet hose to the coolant overflow tank because I probably punctured it with a screw driver trying to push the hose camp all the way on.



A month ago it developed a full on blow out on the highway. Car overheated slightly but only for like 10 seconds as I got it off the road. I had it towed home and it has been sitting in my garage. I am now in a position to work on it again.



I was wondering if anybody else had any problems similar to this. I seem to be the only one. My potential solution is to pull the radiator completely and have someone professionally weld an AN fitting to the outlet to the overflow tank. Does anyone have any thoughts? Also the coolant dumped all over my alternator and now the battery wont charge so I have to replace that as well. Although the alternator may have been on its way out anyway. Does anybody here rebuild theirs? or should I just purchase a new one?



Let me know if you need any clarification on what I am trying to describe.



Any help or opinion is appreciated.

[m3f_TheJDub-E36]

I have the same issue with the fitment of the hoses (Mishimoto rad) but its just a very tight fit, if it was me I would redo it all.

[m3f_Braymond141]

What radiator is it you’re talking about? Anything in the Mishimoto price/style range really isn’t worth your time. The best choices are full stock (alternate use Z3M S54 Rad + Stewart pump) or Zionsville (Fatboy is the most cost effective solution IMO and most elegant) + Stewart.

[m3f_HoonCrepe]

I have the same issue with the fitment of the hoses (Mishimoto rad) but its just a very tight fit, if it was me I would redo it all.

When you say redo it all what do you mean? DO you mean new radiator and hoses? I was thinking about pulling the radiator and putting all the hoses on the radiator side first before re installing it so I can do it at my kitchen table and get better angles on it.

[m3f_HoonCrepe]

What radiator is it you’re talking about? Anything in the Mishimoto price/style range really isn’t worth your time. The best choices are full stock (alternate use Z3M S54 Rad + Stewart pump) or Zionsville (Fatboy is the most cost effective solution IMO and most elegant) + Stewart.

Good question, I will know when I pull it out I guess. I am guessing it is a mishimoto but unsure at this time. Do you have any links to resources for those to solutions? I definitely don't want to go back to the stock m3 parts based on what I have heard and read.

[m3f_TheJDub-E36]

When you say redo it all what do you mean? DO you mean new radiator and hoses? I was thinking about pulling the radiator and putting all the hoses on the radiator side first before re installing it so I can do it at my kitchen table and get better angles on it.

Check the brand but most likely it's eBay and especially with the cooling system you don't want on reliable parts so by redo I mean new.


If it is a Mishimoto you're probably ok to reuse it but you'll want to check all the other corresponding parts that are part of the coolant system while you have it out.




That's how close mine are, if you can't do it in the car I don't think having it out of the car will make it much easier and I definitely wouldn't spend the money like Braymond141 said on an fittings.

[m3f_HoonCrepe]

Check the brand but most likely it's eBay and especially with the cooling system you don't want on reliable parts so by redo I mean new.


If it is a Mishimoto you're probably ok to reuse it but you'll want to check all the other corresponding parts that are part of the coolant system while you have it out.

Okay cool thank you for the quick reply. It seems to me like I have mishimoto hoses on it except the coolant overflow line. It looks like the blue ones I can get on amazon. What other parts would you inspect? Thermostat? Water pump? Sorry if these are noob questions. I am trying to take the best care I possibly can and I am new to wrenching.


That picture quality though! How did you get your hoses on? That's exactly how mine look except the lower hose clamp is essentially sitting on that lump on the outlet from the radiator so offset to the right from yours.

[m3f_TheJDub-E36]

Okay cool thank you for the quick reply. It seems to me like I have mishimoto hoses on it except the coolant overflow line. It looks like the blue ones I can get on amazon. What other parts would you inspect? Thermostat? Water pump? Sorry if these are noob questions. I am trying to take the best care I possibly can and I am new to wrenching.

I would get the stock overflow hose, you probably have a silicone one now that's a lot thicker than the stock one and that's probably some of your problem.


https://www.ecstuning.com/b-genuine-...e/17111723521/


Definitely check water pump and thermostat is good to replace while you're in there but stay OEM, I just went through a nightmare of lower temp thermostats not fitting properly and causing leaks.


The Stewart water pump is the popular choice around here, it's well worth the extra money.

[m3f_HoonCrepe]

I would get the stock overflow hose, you probably have a silicone one now that's a lot thicker than the stock one and that's probably some of your problem.



Definitely check water pump and thermostat is good to replace while you're in there but stay OEM, I just went through a nightmare of lower temp thermostats not fitting properly and causing leaks.



The Stewart water pump is the popular choice around here, it's well worth the extra money.

Okay so stock overflow hose. I have a replacement one already that I bought off amazon because next day shipping when I was itching to fix it. Maybe I should go to bmw to get the stock one though. A stewart water pump. Stock thermostsat. Anything else?

[m3f_TheJDub-E36]

That picture quality though! How did you get your hoses on? That's exactly how mine look except the lower hose clamp is essentially sitting on that lump on the outlet from the radiator so offset to the right from yours.

I had to get both hoses fully seated to get the hose clamps past the flared part of the fittings

[m3f_TheJDub-E36]

Okay so stock overflow hose. I have a replacement one already that I bought off amazon because next day shipping when I was itching to fix it. Maybe I should go to bmw to get the stock one though. A stewart water pump. Stock thermostsat. Anything else?

Check the overflow tank for any cracks or signs of leaking, coolant level sensor, and auxiliary fan switch are the only other things to check.


The hose you got on Amazon is probably fine.

[m3f_HoonCrepe]

Check the overflow tank for any cracks or signs of leaking, coolant level sensor, and auxiliary fan switch are the only other things to check.



The hose you got on Amazon is probably fine.

Alright cool. I was actually looking at aftermarket overflow tanks as well to clean up the look of the engine bay a little bit. Thank you for all your information. I just have to figure out where all those things are now.

[m3f_TheJDub-E36]

Alright cool. I was actually looking at aftermarket overflow tanks as well to clean up the look of the engine bay a little bit. Thank you for all your information. I just have to figure out where all those things are now.

once you start taking everything out it's really easy to get it all back together, I got both the Mishimoto radiator and overflow tank new from my friend for a crazy good deal but they're not what I would call an upgrade, it was just a good deal


Just a heads up It's a nightmare to bleed this radiator:/ I had to take the driver side hose off and fill it from there to get most of the air out.

[m3f_HoonCrepe]

once you start taking everything out it's really easy to get it all back together, I got both the Mishimoto radiator and overflow tank new from my friend for a crazy good deal but they're not what I would call an upgrade, it was just a good deal



Just a heads up It's a nightmare to bleed this radiator:/ I had to take the driver side hose off and fill it from there to get most of the air out.

Okay so just judging from your pictures, that is the same radiator that I have. And now I have even more questions. So when I had the overflow hose blow out it was actually on the way too work and I heard a hissing after I parked the car. I saw the issue and I cut the damaged part of the hose and re attached it. Then I filled the overflow tank with distilled water once the car had cooled down. It then proceeded to overheat on the ride home or at least come really close to overheating on the ride home. When I popped the hood there was no more leaking and no hissing and no obvious signs of leaks besides the massacre that had occurred in the morning. So, how exactly do you bleed this system once I reinstall it?

[m3f_TheJDub-E36]

Okay so just judging from your pictures, that is the same radiator that I have. And now I have even more questions. So when I had the overflow hose blow out it was actually on the way too work and I heard a hissing after I parked the car. I saw the issue and I cut the damaged part of the hose and re attached it. Then I filled the overflow tank with distilled water once the car had cooled down. It then proceeded to overheat on the ride home or at least come really close to overheating on the ride home. When I popped the hood there was no more leaking and no hissing and no obvious signs of leaks besides the massacre that had occurred in the morning. So, how exactly do you bleed this system once I reinstall it?

You probably had some air in the system, there's a lot of great posts on here so I would start by searching but this video covers basically everything on the cooling system for our cars



YouTube (Short URL)