Technical Multijet coolant leak EGR?

[DaveMcT]

This little booger is a joy to drive but it's fighting me all the way. Performance is good engine runs smooth and its sipping fuel.

However, it's using coolant. There is no smell of coolant in the exhaust, no smell of exhaust in the coolant oil is clean and oil level is constant. Worryingly, there are no drips anywhere and the level drops pretty fast when driving though not when left idling. I have just tried some radiator leak sealer just in case it's a small leak that closes up when engine is off. The level is still dropping. Please dont confuse it with that risky rubbish which alleges to fix head gaskets.

I'm about to order a compression tester but it's probably a white elephant as the engine runs so smoothly.

Question 1 - Are there any known coolant leak points on this engine that I should be looking at before the compression tester arrives?

Question 2 - Do HC in coolant (colour change) chemical tests work on diesels?

Question 3 - How do you test for EGR cooler leak?

 

[bugsymike]

This little booger is a joy to drive but it's fighting me all the way. Performance is good engine runs smooth and its sipping fuel.

However, it's using coolant. There is no smell of coolant in the exhaust, no smell of exhaust in the coolant oil is clean and oil level is constant. Worryingly, there are no drips anywhere and the level drops pretty fast when driving though not when left idling. I have just tried some radiator leak sealer just in case it's a small leak that closes up when engine is off. The level is still dropping. Please dont confuse it with that risky rubbish which alleges to fix head gaskets.

I'm about to order a compression tester but it's probably a white elephant as the engine runs so smoothly.

Question 1 - Are there any known coolant leak points on this engine that I should be looking at before the compression tester arrives?

Question 2 - Do HC in coolant (colour change) chemical tests work on diesels?

Question 3 - How do you test for EGR cooler leak?

 

[jrkitching]

I'm about to order a compression tester but it's probably a white elephant as the engine runs so smoothly.

I'd be ordering a coolant pressure testing kit. Small external leaks can be more easily (and safely) detected if the system is pressurised when the engine is cold..

It's got to be going somewhere.

 

[bugsymike]

I would start with coolant system pressure test and if nothing shows then a leak test rather than compression, though as you say running sweet and no obvious head gasket/coolant signs.
Chemical sniffers should show presence of combustion gas whether petrol or diesel.
Fingers crossed if you do a coolant pressure test and find a hose clip or something even if at back of engine.

 

[DaveMcT]

Coolant pressure test. Of course. I'll look into doing that. I have a spare cap so can set up something. There's no signs of an external leak. There's not even a drip from the nasty seal at back of water pump.

If I can get to the EGR hoses, a couple of long nose Mole Grips to clamp them might be enough to prove if it's the cooler. If there's space to get them in.

 

[jrkitching]

If I can get to the EGR hoses, a couple of long nose Mole Grips to clamp them might be enough to prove if it's the cooler.

Brake hose clamps???

 

[jrkitching]

Coolant pressure test. Of course. I'll look into doing that. I have a spare cap so can set up something

Don't go above 15psi. It'd spoil your day if you perforated the radiator.

 

[DaveMcT]

Brake hose clamps???

Same idea but the pipes are about the same as heater hoses so it might not be an option. Don't want the test to force me into needing a new EGR cooler.

This one has both coolant hoses attached. The whole lot sits below the intake manifold. The corrugated metal pipe (with sleeve) goes to the manifold. The shiny part (cooler) is at the bottom end. Access is miserable.

This shows the hoses

This is the view you get from under the car

 

[koalar]

Question 2 - Do HC in coolant (colour change) chemical tests work on diesels?

Yes


Both diesel and petrol can pass the sniff test and still have a head problem

 

[bugsymike]

Surely with that type hose fittings all you need is a length of copper pipe and two hose clips to do a temporary bypass, the way we used to do if a heater matrix was suspect in the old days before it was used as part of the general cooling of the engine.
On my 1.6 Doblo it's all fancy plastic fittings with rubber O rings.
Just a thought if the egr cooler is held on with the two bolts where you were inspecting for egr blanks , presumably it will undo easily so if held back and then with hoses still on you pressurised the cooling system with the tester , if suspect water would seep out to confirm diagnosis.

 

[DaveMcT]

It's not possible to reach down to the EGR. Inlet manifold is in the way. Hopefully I can reach up to the cooler-valve joint. Taking it off entirely will be a nightmare as there's a horrible hinged clamp on the corrugated gas pipe.

I've not got into it yet but access to the EGR would not be worse if they had designed it for zero access. I'm hoping I can just clamp on a couple of long nose Mole grips to stop coolant getting to the cooler. Coolant bypass would be a bit more work but should be doable.

 

[koalar]

I'd be ordering a coolant pressure testing kit. Small external leaks can be more easily (and safely) detected if the system is pressurised when the engine is cold..

It's got to be going somewhere.

You can usually bodge something together

Old radiator cap often come in useful glue a valve in it



Correct it has to be going somewhere

You can't always see steam, gaffer tape a rag to the cap, be damp if the caps faulty

Start the car and see if the hoses go hard

With the cap off look for bubbles in the expantion tank

Hold some kitchen roll over the exhaust, is it slightly pink

Do the carpets get wet

And so on

 

[DaveMcT]

You can usually bodge something together

Oh Yes!

Old radiator cap often come in useful glue a valve in it

I have a spare cap and a bolt on tyre valve

You can't always see steam, gaffer tape a rag to the cap, be damp if the caps faulty

Not tried that but there are no excessive bubbles coming in from the vent pipe

Start the car and see if the hoses go hard

The hoses feel normal. Deffo not like it's being over-pressurised

With the cap off look for bubbles in the expansion tank

Nothing unusual and no exhaust smell. It has a new (nice & clear) rugby ball tank.

Hold some kitchen roll over the exhaust, is it slightly pink

Good idea. Need to try that. But there's no unusual smell.

Do the carpets get wet

Carpets are good and no coolant smell in the car. The way the coolant level drops the car would be swimming and like a sauna if the heater was leaking it all away.

Engine runs smooth and has plenty of power with no hiccups.

 

[varesecrazy]

Hi..late to this..

Do NOT disturb that corrugated hose.. its a crimp fit..will never seal again

Worth ruling out the heater matrix
( especially in this weather.. unlikely to spot a leak )

I have painful experience of both..

 

[DaveMcT]

Hi..late to this..

Do NOT disturb that corrugated hose.. its a crimp fit..will never seal again

Worth ruling out the heater matrix
( especially in this weather.. unlikely to spot a leak )

I have painful experience of both..

I had that corrugated hose separated when the engine was out of the car. The silly hinged clamp had rusted solid (ferrous against stainless). An absolute b1tch to reattach. It's probably impossible with engine in car. I never realised the EGR cooler can leak so didn't test it or consider asking. the solution is probably a silicone hose. They can go to 250C but you still have to get the lips connected.

 

[Trimdoner]

We've had just this problem on our MJ for nine months..... finally sorted.
FWIW, same mysterious water loss, occasional puddle on floor but no sign of where from, ran perfectly and never overheated on long journeys.
Left it ticking over for 1hr 20 mins, not a drop lost. Turned it off, not a drop lost - until about 10 mins later when a puddle appeared........!

Turned out the heater to engine hose above the egr had a 'balloon' on it, which for some reason worked like a valve, only leaking when nobody was looking. Pity it was such a pig to change

 

[DaveMcT]

If I get to prove the leak is within the EGR, it will get a delete by total removal. It's the most horrible setup with virtually zero access. Well done Fiat engineers. I've clamped the walking stick hose from EGR to cabin heater - easy from below but car has to be jacked up and supported. The EGR water hose from engine thermostat needed the battery box and ECU taking out. The hose is now clamped and battery put back so we will see how the test drive goes. Putting in a bypass hose is more elegant but will happen if/when the EGR cooler leak is proven.

Off now for a test drive…

I’ve just done a distance that would have dropped the coolant level most of the way from max to min. The level is unchanged. So that’s it. EGR cooler has a leak.

Now to get the effin thing off the car and sort out the coolant bypass.

 

[jrkitching]

If I get to prove the leak is within the EGR, it will get a delete by total removal.

I'm not passing judgement on the merits of doing this, but I wouldn't want to see you have future MOT problems after all your efforts.

Just be aware of the wording in the current version of the MOT testers manual. If you modify this is a way that isn't obvious from a visual inspection, and it passes the emission check, then what the MOT tester doesn't know ....

 

[varesecrazy]

Pretty sure the EGR can stay

Just re.route the coolant flow

 

[DaveMcT]

Thanks for the comments. I was thinking about this.

On the 1.4 petrol, the hose from thermostat to heater is a more or less straight "tube". The M-jet intercepts it with the EGR. As Mike suggested, I'm going to bypass the EGR cooler to confirm the fault is gone (belt, braces, etc.). However, the gas is cooled, presumably so the warm exhaust gas doesn't (1) damage the inlet manifold and (2) cancel out the turbo intercooler.

The EGR unit is held to the engine with the two bolts visible on the RH in Varese's picture. They are about 100mm long. I'm concerned about that nasty flange joint in the corrugated pipe. The pipe is surprisingly stiff, making the clip horrible to fit. A silicon hose joiner is probably a better idea. It's rated to 250 degs C.

More to follow.