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New 5.9 electric fan fix

9K views 6 replies 3 participants last post by  Jeep95XJ 
#1 · (Edited)
OK as i stated in a previous thread my low speed fan switch went bad on my niner. Now i was told "the switch is no longer made" "you cant find it" Well in part people were right. However thats not good enough for me. I did find the switch at a dealer in MO however im not paying $95 + whatever the dealer wants to add onto it seeing as they have the LAST one in the country! Well i did a little homework. The stock low speed switch kicks on at 213* and high speed kicks on at 220* Before today i had no fan till 220* and obviously we cant have that. Now Duralast part # SU109 or 5U109 (same part some autozone locations just cant tell the difference between a 5 and a S) Is for a 86-87 Buick Grand National. Direct plug and play. 3/8 NPT same electric plug 100% drop in. Kicks the fan on at a cooler 200* That along with a 180* stat and so far so good. Also decided to replace the stock 1998 upper and lower hoses while i was at it. No parts store has 5.9 hoses. Dealer only at almost $500 a pair. Well the stock 5.2 hoses are exactly the same. Just cut them in half and fit the fan switch sending unit T fittings into the hoses. Flushed the block and radiator and refilled. Hope this helps out any of you guys with niners that have low speed fan problems or just want to run a little cooler. Another thing i see guys doing is using this Buick fan switch as a low speed and using the stock low speed switch in place of the high speed. 200* low 213* high. If my stock low speed switch worked id do this also. Ill follow up on this thread when i find a plug and play switch to replace the high speed 220* switch as a plug and play with a switch that kicks on about 210* Should work perfectly with the 200* low speed switch. Id like high speed before the 220* mark. Thats just me though. Ahh and yes i was worried about having heat on cold days. Heat still cranks just fine. :thumbsup:
 
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#2 ·
SWEET!! Screw the stealers! Yankee ingenuity wins again!
 
#4 ·
Actually yes! They are the same! The upper and lower hose both use the same switch. The antifreeze in the lower hose will always be cooler due to the fact that it has already passed through the radiator. If it's running hot enough for the gauge to read 220 the antifreeze in the lower hose is around 212 which is quite high. That kicks on a 2nd relay which kicks on the high speed. I actually found a better switch than the GM one i posted above. I ordered it from summit. It's made by becool and the part # is 75009 The fan kicks on a little later but its much closer to stock spec. Id run a 195* stat with that switch. You can use one in the upper and lower hose and it will function just like stock. If you want to run cool and run the 180* stat juse use the GM switch listed above.
 
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