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Engine overheats after Do88 radiator upgrade - fans stop working intermittently (with pics)

774 Views 8 Replies 4 Participants Last post by  Aven
Hey all,
I've been scratching my head around this for the past month and can't pinpoint the problem, seeking your advice.
This post has three sections to help shed a light on what I've done with the car so far. Might be useful to help diagnose the problem. You can just skip to section 3 to check the problem:
1- Job 1
2- Job 2
3- The problem

My radiator cracked and started leaking, so I decided to treat my old girl (09 XC60 T6) and upgrade to do88 WC-340 radiator, along with the following:
  • ipd Thermostat (glad i did since it came out in pieces)
  • ipd Intake manifold gaskets (since I removed it to reach the thermostat)
  • OEM Upper and lower radiator hoses
  • OEM Spark plugs (car is 130K Km and since i was ordering parts i decided to replace them too)

Automotive radiator part Wood Musical instrument Gas Folk instrument

The parts

Plant Automotive tire Motor vehicle Tire Wood

The car during work. with no lift available (but the car jacked still) It was just so much easier to take out the front end in order to get into the tight spaces and slide both the fan and old radiator out)
Automotive tire Camera accessory Bicycle part Rim Auto part

Old vs new thermostat. Glad i replaced it as it was apparently broken due to its age.

Automotive tire Motor vehicle Light Automotive design Automotive exterior

new thermostat in place

Did the job within 3 days and vacuum-filled OEM coolant. The car ran perfect for a couple of days until it started leaking coolant again on top of transmission. and here is when i saw the first overheating warning. I parked immediately and didn't drive the car since.
I figured since im loosing coolant, air might be creeping through the water pump gasket since it gave up (maybe cuz of the vacuum filling?)
Thus, I figured yeah it's an old gasket let me do another job and replace:
(without the steel pipe connected to water pump housing)

Automotive tire Black Gear Motor vehicle Alloy wheel

Old water pump was leaking and splashing water as serpentine belt spins.
Automotive tire Motor vehicle Alloy wheel Rim Gas

Yep, doesn't look pretty. I did then clean up as much as i could where the gasket sit.

Automotive tire Font Rim Art Automotive wheel system

Old vs new pump. The old one is totally fine, but oh well, a new one is installed.
Musical instrument accessory Camera accessory Bicycle part Bicycle fork Wood

Old vs new thermostat hose, the bottom part includes what seems to be a flow/check valve which was completely missing in the old hose!
Water Liquid Fluid Automotive lighting Flash photography

Inside of new (left) vs old (right) hoses where the spring and plastic parts of the valve are missing. I found the spring stuck at the end of the pipe, but the plastic parts in the middle are gone (scared to think inside the engine!)

Gauge Motor vehicle Measuring instrument Auto part Font

After the job, i filled the car with coolant (vacuum-filled) and pressure tested the system with finally no leakage at all. I even tried burping the system to make sure no air is trapped in the cooling system.


After the second job, the car runs fine in the first 20 min, I warmed it until it reached 98 C (208 F). In both driving and at idle, the moment i reach 98 C (208 F) the fans run at 33% to cool the engine back to 96 C (204 F) and then they stop. and then again at 98 C and so on... and it seems to do that for a couple of times until suddenly the fans do not engage and the car shoots to around 110 C (230 F) before i shut it off.
It also happens much quicker when i turn on the AC, where the fans work well for a while, then shut off and i lose cool air and the engine overheats again.
However, the moment i shut the engine off, the fans engage at 100% to cool the engine for 6 min.

In Vida I can engage the fans at 100% and they run fine.

So im really puzzled on what the problem might be. Did the fan module malfunction despite working fine in above scenarios? Is it something else I'm missing?

appreciating your feedback.
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Shot in the dark but how reliable are the ipd thermostats? I'd probably replace that with OE personally.
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