Inlet manifold

[Deepfat]

Background 2002 TF135: I have a very small water leak which I'm having trouble locating I've been all under it and only found a pink stain near the crank pulley (1st spotted by MOT guy). I had no history on the belt so I fitted a new belt/pump but upon removing them they appeared nearly new, I did notice some staining above the pump but discounted it at the time.
Looking on line I discovered the inlet manifold may be the cause so can I tell if it's a plastic or alloy one (vin?) without removing the engine cover so I can order the parts before starting the strip.
On line it was also suggested that the cylinder 4 area was the most likely spot to leak, if the TF is 1-4 from the crank pulley as per norm then it's the wrong end if I take the previous staining (discounted) as witness so where should I look to possibly confirm.
Before anyone mentions you know what the car performs faultlessly, the temp is rock steady even in the weather we are currently experiencing, the new antifreeze (cam/belt change) is clean and the oil although due a change is a lovely clear honey colour.

[RobboMC]

Stains at the crank pulley can be quite misleading. My story is about oil, not coolant, but the idea is the same.

I found oil leaking behind the crank pulley, so changed the crank seal ( and timing belt )

3 months later still leaking - so went looking, found oil on pulley so changed seal again ( and timing belt )

3 months later still leaking - went looking further, found oil around camshaft seals,
changed both pulley end seals and crank seal again ( and timing belt ) and cleaned out out breather system

6 months later still leaking; this time replaced all 4 camshaft oil seals, ( and timing belt and water pump) tightened down cam cover.

FIXED!

The moral of the story is the liquids run down the warm engine to the crank pulley. With coolant more likely to boil away I would be
looking towards the water pump seal. You mention the cam belt looked new, what about the water pump, a new one will be nice and shiny.


If you're going to strip it, perhaps do the water pump as well as the manifold seal.

[mgtfnut]

Years ago, 2004 ish, I noticed some pink residues around the water pump, and I can't recall the details now, but there was talk of this being common.
It may have been that there was an evaporation ledge that held coolant while it evaporated from the seal.
At the next cambelt change, I changed the water pump and have never seen anymore pink staining. I think I left the same water pump on for many cam belt changes with no ill effects, however I changed the lot last year and the water pump looked like new after many years.
I never experienced any coolant loss, or any other problem.
Earlier F model with the plastic inlet manifold was more prone to gasket leaks, but I think the problem went away with the aluminium TF manifold.
As an aside, the water pump on my Suzuki is original from 1985/86 and 308k miles!

[talkingcars]

...can I tell if it's a plastic or alloy one (vin?) without removing the engine cover so I can order the parts before starting the strip....

You can see the inlet manifold from the boot. Plastic is black, alloy is bare metal.

We (my son) has removed the plastic inlet on our project F to replace the thermostat and are replacing it with an alloy one as they are less prone to leaking as they don't warp. We are actually using a MEMS3 version (as that was in my shed) by swapping the sensors and injectors.

[Deepfat]

Thanks for all the advice, I feel a right idiot constantly checking the coolant and not noticing the inlet manifold right in my face DOH! it's an early car so it is plastic so I should probably start to look for an alloy one. I still can't see any signs of a leak but I'm going to borrow a mates endoscope to have a good look, I don't want to end up going down another dead end.

[mowog73]

... are replacing it with an alloy one as they are less prone to leaking as they don't warp.

The issue with the plastic inlet manifold and coolant leaks is more so related to the inlet manifold gasket becoming hard, shrinking and leaking coolant as a result, not due to warping. Best to change in the inlet manifold gasket to the updated viton one.

[talkingcars]

... are replacing it with an alloy one as they are less prone to leaking as they don't warp.

The issue with the plastic inlet manifold and coolant leaks is more so related to the inlet manifold gasket becoming hard, shrinking and leaking coolant as a result, not due to warping. Best to change in the inlet manifold gasket to the updated viton one.

So why doesn't this happen to the alloy manifolds?