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Hi all! I need advice on my engine fan. I am planning to paint/powdercoat my engine fan into red color. But upon noticing the said item on detail, I encounter some 'spots' and i thought it will be a hindrance in the painting process.
(1) How should I paint my engine fan and what do I need?
(2) What should I do with the spots/cracks?
Planned result Current condition with spots/cracks
Thanks as always!
If you havent already, definitely perform a search of the forums. Lots of threads on the delicacies of the engine fan.
Its magnesium and pretty sure you dont want to try to powdercoat. Also want to make sure your paint thickness does not interfere with the housing. For the old coating, you'll need something relatively delicate like media blasting.
If you havent already, definitely perform a search of the forums. Lots of threads on the delicacies of the engine fan.
Its magnesium and pretty sure you dont want to try to powdercoat. Also want to make sure your paint thickness does not interfere with the housing. For the old coating, you'll need something relatively delicate like media blasting.
Yeahhh I have, exactly the never-ending debates cause confusion on my side . But how about durability? Is paint actually durable to the elements exposed by the cooling fan?
Your fan looks to have been PC'd or painted previously, yes? If so, I would have it plastic or walnut shell media blasted and then refinished.
Paint may be preferred due to potential clearance issues with the ends of the fan blades and the housing.
Ha! phoneyman posted as I was writing... ; )
Yeah nine9six, it probably has by the previous owners and i think it was a terrible paint/PC job. So it must be first media blasted to remove the old layer, then repainted?
Paint will not hold up as well as powder coat. Magnesium can be powder coated, if done correctly. The OP's fan is a mess, buy a new one. Once the magnesium is comprised, you run the risk of having the fan self destruct, sending metal bits into the deck lid.
I have experience painting but have not replaced a fan or evaluated one for potential failure. For this reason evaluate my thoughts below at your own risk.
I see serious corrosion on your fan. I would make a close inspection of the fillets at the base of each blade looking for signs of cracks. If you see cracks in the metal, the fan should be replaced even if you don't paint it. Not sure how to prep the fan for painting but it may be worth having it sand blasted to clear the oxide from it's surface. Doing this before inspection may be a good way to go. My understanding is that most catastrophic fan failures have to do with the fan rubbing the housing inducing a fatigue failure in the base of the blades. To minimize the concern about paint build-up I would just gun paint the fan from the front. I would use single stage, non clear coat, automotive 2K urethane paint to maximize durability. I would very lightly paint the outward facing edges of the blades to foster good edge adhesion. Use a compatible primer. You may find the paint supplier can add something to it so it has a filling property and can be sprayed in several coats and then lightly sanded to reduce the appearance of pitting from corrosion.
A DIY approach may be to strip the fan using a chemical paint stripper. Then you can do a thorough inspection before you spend any money on it. Take hi res photos so others on this forum can have a look. It is really hard to tell what you've got until it is cleaned up and old paint removed.
The paint looks pretty bad, but I don't see any detectable damage to the magnesium. I agree with AllanH. You can sandblast or use some aircraft paint stripper (works great), and then carefully inspect for any major cracks or corrosion. Minor surface issues can be filed/sanded down (start with 350, and gradually work up to 500, 800, and 1,000 grit), and it's a good idea to sand a little off the tips of the blade to make room for the new paint. Powder coating is the best way to go, but a good paint job (read preparation) followed by some clear worked great for me. Good luck and have fun with the project!
Check for run-out as well, it does not look like any impacts on the blades but the adhesion for the previous paint is definitely poor. The fan should be pretty straight when spun, that is another issue that can cause problems. I just recently replaced an alternator on a clients car twice ; the alternator shaft broke inside the alternator case on a brand new unit. We concluded it was either a defect on the new alternator, or the fact that the fan has some significant runout may have caused harmonics - it happened near redline.
The fan painted in a cleaned up shroud always looks good. As previously mentioned, a critical part is making sure the fan clears the shroud - too much material on the fan at the edges and the clearance goes to zero, and now you have a rubbing fan which can lead to failures.
Paint will not hold up as well as powder coat. Magnesium can be powder coated, if done correctly. The OP's fan is a mess, buy a new one. Once the magnesium is comprised, you run the risk of having the fan self destruct, sending metal bits into the deck lid.
Unfortunately, fans are crazy effin expensive.
I thought about chemically stripping, but not sure if stripper chemicals will attack the micro structure of the magnesium. If the chemicals do not have a detrimental effect on the parent material, this would be the preferred method of stripping if you decide to perform NDT with dye penetrant and check for cracks.
You could go online and buy yourself a small NDT dye penetrant kit. The downside to media blasting, is that it smears the metal and can mask/hide linear indications (potential cracks).
^this is why the forum searches are so important. I understand aluminum, steel, and even titanium, but magnesium is a bear most people havent dealt with in car parts. Fans are spendy, but I'd probably buy a new one just to avoid the pitfalls of screwing up the job. Or just send Steve W or the equivalent a blank check and tell me what to do.
12-14-2016, 12:31 AM
Refreshing the engine fan
. But how about durability? Is paint actually durable to the elements exposed by the cooling fan?
