Clogged Radiator Symptoms

[rieosiris]

I've been chasing a cooling gremlin on my Cousin's 91 535im. Long story short, we've done the head gasket, t-stat, and converted to an electric fan. However, the darn thing is still overheating after repeated bleeds. Out of dumb luck, I happened to put my hand on the radiator and realized that only the top 4" of it was hot, the rest was absolutely cool to the touch (after 10+min of running). I'm assuming that indicates some sort of blockage? I've never heard/seen/felt it be that severe. Is there anything special about these radiators that would prevent me from going to a local radiator repair place and having them clean it? I'd hate to drop $150 on a new one if it's not needed. Thanks!
-Lloyd

[e34.535i.sport]

Not too sure on the radiator side, although if it's causing overheating the cost of a new one is much less than another HG job... Are you bleeding the system with the interior heater blowers on full and uphill etc?

Those throwing stars look amazing... I'm on the look out for some but they're like rocking horse **** in good condition.

[bubba966]

Nothing special about the rads that I'm aware of. Just had mine out a couple of weeks ago to seal up a leak in the side tank. Took the garden hose to the bottom hose port on the rad and flushed it out for good measure.

No reason you can't just pull it out and try that yourself. If you get a lot of crap coming out of it then you know you've got a problem. Also should be able to tell if it's clogged if you can't run any water all the way through it.

[Paul in NZ]

I've been chasing a cooling gremlin on my Cousin's 91 535im. Long story short, we've done the head gasket, t-stat, and converted to an electric fan. However, the darn thing is still overheating after repeated bleeds. Out of dumb luck, I happened to put my hand on the radiator and realized that only the top 4" of it was hot, the rest was absolutely cool to the touch (after 10+min of running). I'm assuming that indicates some sort of blockage? I've never heard/seen/felt it be that severe. Is there anything special about these radiators that would prevent me from going to a local radiator repair place and having them clean it? I'd hate to drop $150 on a new one if it's not needed. Thanks!
-Lloyd

any decent radiator place would be able to do it....i am of the other school of thought tho....why spend bucks on a old radiator when it might crack at he neck etc at any moment..get a new one

[attack eagle]

exactly, why go to all that trouble only to have it crack on you when you put it back in?

$158 shipped on a Behr is a damn great deal

[Tiger]

I don't think it is the radiator. My suspicion is the water pump and/or thermostat.stuck.

[Ferret]

I don't think it is the radiator. My suspicion is the water pump and/or thermostat.stuck.

I agree, check your pump is good first - unplug the aux heater pump and see if the heater will get hot without it...

[rieosiris]

Boy do I feel like a doofus. After cleaning the radiator out (there was some gunk in it), I put everything back together with some Prestone radiator flush. The darn thing still started to overheat. Top hose was hot, bottom hose and pax side of the radiator were cool. Tracing the loop I figured there must be something preventing the return of fluid from the radiator. Yep...Thermostat was in backwards! Swapped it around, bled the system and all is well. I can only imagine how long it's been like that. I wonder if the country bumpkin mechanic my cousin got stranded at put it in that way...causing all the following damage. Anyway, thanks for all the quick responses. I need to visit the board more often!

PS: Thanks for the compliments on the T-Stars. IMHO it's the only OEM way to go (2nd only to a full 17x9 staggered setup, or factory M Parallels). I took her out for some exercise tonight...got to blow the carbon out =o)