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Tired Of Replacing Overheated/blown Ptu's On Your R32

funkymonkey

By funkymonkey,
in General Maintenance

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funkymonkey Grand Master

funkymonkey

Posted
Posted

Pretty simple mod, anyone can do it as long as you have a screwdriver and/or a size 8 socket wrench, and can go to your local hardware shop to buy some long bolts

On R32's the PTU is mounted directly onto the rocker cover, and unfortunately is subject to a lot of heat from the engine. This can cause the PTU to overheat and as a result the contacts can warp and wires melt or get brittle from heating/cooling down repeatedly for many years of use. The PTU comes with a heatsink, but unfortunately getting airflow over the PTU can be an exercise in futility, esp if you have a intake pipe running across your engine and strut reinforcement bars etc.

The solution is to space the PTU away from the engine or mount it onto the firewall. The latter can be a bit tircky with wires having to be extended and new holes having to be drilled onto the firewall. By spacing the PTU higher up, you can actually move it into the path of airflow under the bonnet, also by getting some space between the engine and the PTU you can improve heat dissipation from the ehatsink (which is unfortunately on the bottom of the PTU).

The pic should be self explanatory as to what you need to do:

post-256-1195987270.jpg

post-256-1195987270_thumb.jpg

I just used these ones I had lying around in the garage, but ideally I'd wanna make a sleeve to go over the exposed thread, just in case the nut under the PTU holding it up comes loose.

GeeTR Grand Master

GeeTR

Posted
Posted

Nice mod, I thought bout sanding down the fins on the unit and gluing a taller heat sink, but this is far less work ;)

productLarge_1155.jpgproductLarge_703.jpg

Whats PTU suppose to stand for tho? its an igniter module, havent heard it called anything else before

Power Transistor Unit

funkymonkey Grand Master

funkymonkey

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I cable tied mine to those metal lines further up ;)

hehe thought of cable tying it to my ABS lines as well... the heatshield that was on it was so brittle when i tugged at it a little it just crumbled... so I went for a ghetto solution.

bubba Grand Master

bubba

Posted
Posted
an even simpler way is to unbolt it, turn it upside down, and bolt it donw again

that way, the heatsink faces up and allows the heat to dissipate, yet you use no new parts and it mounts in the stock location

That's what I did, also don't have the coil cover so it's only held down by one bolt in the corner (with the earth strap) into one of the coil cover bolt holes. It's kind of hanging out over the coils with the fins pointing up.

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