[K9Leader]

My 2010 E91 x-drive with AT has been losing coolant. I pulled the belly pan and found the leak is on the left side, possibly where the upper hose connects to the radiator, possibly at the drain plug, but more likely, a crack in the plastic at the neck that connects to the upper hose. First posted over on the maintenance page and got some good suggestions and guidance. I've ordered a pressure test kit to be sure, but I've a feeling it may be new radiator time.

Not surprised as it is 12 years old and 138K miles.

[fazm]

My advice: Go whole hog and do the CSF aluminum radiator, do the water pump and t stat if they haven't been done yet, and replace every easily reachable hose.

It's a half day of work and it's all easier with the radiator out.

[K9Leader]

Originally Posted by fazm

My advice: Go whole hog and do the CSF aluminum radiator, do the water pump and t stat if they haven't been done yet, and replace every easily reachable hose.

It's a half day of work and it's all easier with the radiator out.

Yes, that's what I'm thinking. Water pump and t-stat were done last year so those are good. Is the aluminum radiator better? I've heard you just trade one set of issues for another.

[CTinline-six]

Originally Posted by K9Leader

Yes, that's what I'm thinking. Water pump and t-stat were done last year so those are good. Is the aluminum radiator better? I've heard you just trade one set of issues for another.

The aluminum radiator shouldn't crack like the plastic one, but I have an N51, so I'll have to get the special radiator when mine breaks.

[mainbearing]

Delaware incorporates California's CARB requirements, which means you may have an N51B30 using a $600 ozone-reducing radiator.

It does look like that radiator plastic tank is the problem. As another said, change out all the hoses you can reach while doing the job, plus the Mickey Mouse flange to an aluminum one if not already.

And remember the small vent hose over the radiator to the reservoir tank too:
https://www.e90post.com/forums/showp...0&postcount=52

[fazm]

Originally Posted by K9Leader

Yes, that's what I'm thinking. Water pump and t-stat were done last year so those are good. Is the aluminum radiator better? I've heard you just trade one set of issues for another.

The aluminum radiator is metal edge to edge, so you don't have the plastic tanks on the side. The only issue I've had is the fitment, I had to use some elbow grease to bolt mine in.

[K9Leader]

Originally Posted by mainbearing

Delaware incorporates California's CARB requirements, which means you may have an N51B30 using a $600 ozone-reducing radiator.

It does look like that radiator plastic tank is the problem. As another said, change out all the hoses you can reach while doing the job, plus the Mickey Mouse flange to an aluminum one if not already.

And remember the small vent hose over the radiator to the reservoir tank too:
https://www.e90post.com/forums/showp...0&postcount=52

Mine is an N52 so the special N51 radiator is not an issue. Yes, I will change every component I can get to. Mickey Mouse flange was done two-three years ago when I did the OFHG and the old flange crumbled to dust when I tried to remove it.

[K9Leader]

Originally Posted by fazm

The aluminum radiator is metal edge to edge, so you don't have the plastic tanks on the side. The only issue I've had is the fitment, I had to use some elbow grease to bolt mine in.

Poking around on the various seller sites, I see the all aluminum CSF radiator is listed by FCPEuro as only for manual transmission yet on another site, UROTuning, it is listed as for both manual and automatic. This E91 is an automatic so I will need to figure this out. My E82, which is a year newer so I can expect to have to do this same repair on it sometime soon, is a manual and I likely would go with the CSF all-aluminum radiator.

[tcphoto]

I don't get why BMW does the plastic welded radiators, they either split at the seam or the connector. I don't know if $450 is worth the aluminum versus $250 for the Nissen radiator, I put the Nissen in my E46 and was happy with it.

[K9Leader]

Originally Posted by fazm

The aluminum radiator is metal edge to edge, so you don't have the plastic tanks on the side. The only issue I've had is the fitment, I had to use some elbow grease to bolt mine in.

Poking around on the various seller sites, I see the all aluminum CSF radiator is listed by FCPEuro as only for manual transmission yet on another site, UROTuning, it is listed as for both manual and automatic. This E91 is an automatic so I will need to figure this out. My E82, which is a year newer so I can expect to have to do this same repair on it sometime soon, is a manual and I likely would go with the CSF all-aluminum radiator.

Just checked with FCP tech and they said that the difference is the drain plug and that there might be a different drain plug that would allow its use for an automatic but they don't carry it and the CSF info only specifies the 7001 is for manuals. I will probably just go with an OEM/aftermarket radiator for the E91. What are the thoughts on the Mahle Behr or the Nissens or the CSF 3718 vs. the Genuine BMW?

[StradaRedlands]

Originally Posted by K9Leader

Poking around on the various seller sites, I see the all aluminum CSF radiator is listed by FCPEuro as only for manual transmission yet on another site, UROTuning, it is listed as for both manual and automatic. This E91 is an automatic so I will need to figure this out. My E82, which is a year newer so I can expect to have to do this same repair on it sometime soon, is a manual and I likely would go with the CSF all-aluminum radiator.

Just checked with FCP tech and they said that the difference is the drain plug and that there might be a different drain plug that would allow its use for an automatic but they don't carry it and the CSF info only specifies the 7001 is for manuals. I will probably just go with an OEM/aftermarket radiator for the E91. What are the thoughts on the Mahle Behr or the Nissens or the CSF 3718 vs. the Genuine BMW?

Consider contacting CSF directly: https://csfrace.com/
They have to have an option for cars with automatics. That's what, 90% of the market?

[fazm]

My CSF was universal. There's a plugged spot for a hose that goes with the automatic transmission. I got #7001 and it claimed to be universal. You should be good to go if you're working on a LCI.

[johnnyorange]

Originally Posted by K9Leader

Poking around on the various seller sites, I see the all aluminum CSF radiator is listed by FCPEuro as only for manual transmission yet on another site, UROTuning, it is listed as for both manual and automatic. This E91 is an automatic so I will need to figure this out. My E82, which is a year newer so I can expect to have to do this same repair on it sometime soon, is a manual and I likely would go with the CSF all-aluminum radiator.

fwiw i emailed fcpeuro that the info on the csf 7001 radiator on their page stating applicability only to manual trans cars was incorrect, and emailed a link to the csf page showing applicability to AT and 6MT. they confirmed receipt and thanked me, but I do not believe the product page on fcpeuro.com is updated yet.

[ryan stewart]

Originally Posted by fazm

My advice: Go whole hog and do the CSF aluminum radiator, do the water pump and t stat if they haven't been done yet, and replace every easily reachable hose.

It's a half day of work and it's all easier with the radiator out.

Same. People rag on me for over-replacing parts but I find it a lot easier to shotgun stuff. Pretty much the only ones hard to reach once you remove the rad is are the lines going to the firewall, and even those can be done with the intake on if youre creative.

Plus, if yours is like mine, those are WELDED together from years of the heat cycling and broken down coolant and seals gluing the connectors together. So its easier to just remove the rad with all of the hoses still attached (just cut if needed.

[krhodes1]

Originally Posted by tcphoto

I don't get why BMW does the plastic welded radiators, they either split at the seam or the connector. I don't know if $450 is worth the aluminum versus $250 for the Nissen radiator, I put the Nissen in my E46 and was happy with it.

Because they are cheaper, and usually last several multiples of the warranty period. The plastic/aluminum radiator in my Volvo V70 lasted 18 years, I doubt my BMWs will last THAT much less long. I can't see putting anything but another one just like it in it when the time comes.

Of course, with my N51 128i I hope that time comes while BMW will still pay for it! But no choice in that car, unless I want to stare at a permanent CEL.

[autoart]

csf also makes a plastic radiator. I installed mine about a year ago. its $120 at Rockauto

[Efthreeoh]

Originally Posted by krhodes1

Because they are cheaper, and usually last several multiples of the warranty period. The plastic/aluminum radiator in my Volvo V70 lasted 18 years, I doubt my BMWs will last THAT much less long. I can't see putting anything but another one just like it in it when the time comes.

Of course, with my N51 128i I hope that time comes while BMW will still pay for it! But no choice in that car, unless I want to stare at a permanent CEL.

I finally replaced my original factory radiator at 350,000 miles after deer hit No. 4. It wasn't leaking, but it did get twisted a bit when the core support cracked. I sourced an aftermarket Behr, which was around $140 IIRC. Some 55,000 miles later, in for a 4-wheel alignment, the "Tech Inspection" found the radiator was leaking at both bottom corners from the side tanks. This was with the engine cold and the system pressurized for leak detection. I never smelled coolant, never saw coolant dripping from the belly pan, never had a low coolant light event, but sure enough when I pressure tested the cooling system, there were a few drips.

I just took my big-ass genuine Channellocks and re-crimped the side tanks. It's been 10,000 miles since.

[K9Leader]

Originally Posted by johnnyorange

fwiw i emailed fcpeuro that the info on the csf 7001 radiator on their page stating applicability only to manual trans cars was incorrect, and emailed a link to the csf page showing applicability to AT and 6MT. they confirmed receipt and thanked me, but I do not believe the product page on fcpeuro.com is updated yet.

Yes, I talked to a tech at URO Tuning and he confirmed with CSF applicability to both AT and 6MT. FCP Euro continues to indicate manual only, though.

I went ahead and ordered all the parts I will need for the system refresh on the E91 and went with the CSF OE replacement (plastic ends). When it comes time to do the E82 I will go with the high-end CSF all-aluminum.

[moebiuz]

Originally Posted by autoart

csf also makes a plastic radiator. I installed mine about a year ago. its $120 at Rockauto

How is it holding now? Im about to buy that plastic one.

[moebiuz]

Originally Posted by K9Leader

Yes, I talked to a tech at URO Tuning and he confirmed with CSF applicability to both AT and 6MT. FCP Euro continues to indicate manual only, though.

I went ahead and ordered all the parts I will need for the system refresh on the E91 and went with the CSF OE replacement (plastic ends). When it comes time to do the E82 I will go with the high-end CSF all-aluminum.

How is your CSF OE radiator been doing? Im about to buy it

[pbedrosi]

Originally Posted by moebiuz

How is your CSF OE radiator been doing? Im about to buy it

Me too.....about to order on Rock Auto - it's under $100. MAHLE/BEHR has horrible reviews on FCP Euro. Wondering how CSF OE fits and holding up.

CSF website lists the same Rock Auto suggested part number, 3718 for E91/AT/AWD/LCI.

[Hoody007]

Originally Posted by pbedrosi

Me too.....about to order on Rock Auto - it's under $100. MAHLE/BEHR has horrible reviews on FCP Euro. Wondering how CSF OE fits and holding up.

I'm sure CSF is fine. The Behr one is indeed crap. PO installed one in my car, 8 months later it was leaking. Replaced it with an OE BMW one.