stx550 intercooler failure

Hi has any one else had an issue with the intercooler on their 3ltr v6 diesel? I was looking over my new toy today and noticed the intercooler top tube has expanded like a balloon. No hoses were off and I havent heard anything abnormal while driving it.

I used to sell truck intercoolers and when we saw something like this it was thought to have been from faulty internal baffling...although it is hard to fault find with a grinder.

the car only has 5500kms and runs well albeit not as grunty as I thought it should be for the claimed power and torque

please excuse the upside down phone picture...it was a mission just to get the picture

If you are talking about the wire wrapped hose on the RHS then yes mine split on the inside of the bend. Replaced under warranty - no further issues, YET!

That's crazy. I wonder what the temps are like in there - have they used an alloy that has too low a melting point, and it's softening enough to do this?

Charge air temps should be somewhere in the 200-300C range, and aluminium should be getting (workably) soft around over 400C - I wonder if your charge air temp is rising higher than that? Sure the turbo sits on the back of the "V" in the hot zone, but you'd think the charge air shouldn't get that much hotter than a 4cyl once it's flowing.

This is the first I've seen of it. The intercooler definitely needs replacing, it'll be a warranty job too, but it's interesting how it happened - it'd be really cool to find out what the intercooler's intake and outlet temperatures are (which will also give us an idea of its thermal efficiency).

Very interesting I have just done an intercooler as well booked monday for replacement oil every where, Mine is leaking from the tank seals. Have you had any other problems? It split the large rubber hose at 30000, But at 800 km's to 10000 kms spent every second week at dealership because while sitting in traffic stopped at lights etc. You would go to accelerate away and there would be no throttle. Engine still running but no gas.

does anyone else with a 550 notice a boost bleed off noise when they lift off the gas. Im am wondering whether the intercooler actually has a hole in it as well as swelled up

Jase V9X said:

If you are talking about the wire wrapped hose on the RHS then yes mine split on the inside of the bend. Replaced under warranty - no further issues, YET!

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not the hoses....my issue is with the alloy intercooler tubes. take look at the picture to see what I mean.

Would have to know the temps.

TigerST said:

Would have to know the temps.

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and that will tell you.....??

I can get the temps by using a portable pottery thermometer.....but what will it tell you about the cooler failure?

Looks like a manufacturing fault.

Like old Tony said 400 would be the workable of alloy so if its say 450 then that would explain the blow out. Just a thought could be wrong.

Wow - are you guys suggesting that 450c air is coming from the turbo and entering the Intercooler.. Surely that is not even possible..

Christ, if there was 70C air entering the combustion chamber it would be bad enough - 450C would flash the fuel before it was compressed..

Even if you factor in heatsoak - surely it would be neigh impossible to get Intake temps over 100c...

And if it is, then the intercooler is adding heat, not taking it away..

Well went you look at the possibly of egt can reach 1000c its ways possible that the air it the turbo could be pretty high.

I can understand a combustion of flamable liquid reaching 600+ degree's.. If IAT's ever got over 100 then I would be worried..

It would flash evaporate the fuel in the intake..

And power would be non existant.. A quick google shows that a typical Navara Intake temp on a 35 degree day is "60-80C"...

At this point the ECU cuts boost..

So no chance of it getting to 400...

Black_Outlaw said:

I can understand a combustion of flamable liquid reaching 600+ degree's.. If IAT's ever got over 100 then I would be worried..

It would flash evaporate the fuel in the intake..

And power would be non existant.. A quick google shows that a typical Navara Intake temp on a 35 degree day is "60-80C"...

At this point the ECU cuts boost..

So no chance of it getting to 400...

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Diesel is direct injected, it cant flash. But your right, Im guessing you would need 40x more
boost to get ambient air to those temps.

in theory turbo outlet temps should roughly be around 270c....say 300c.
that in no way means the IC is at that temp. it would be a completely useless IC if it was.
but people have but far hotter intake air through an IC without it failing.

the above problem is simply caused by the cheap IC nissan use. when you get to those pressures piping becomes really interesting and you need quality otherwise it will fail.

Black_Outlaw said:

Wow - are you guys suggesting that 450c air is coming from the turbo and entering the Intercooler.. Surely that is not even possible..

Christ, if there was 70C air entering the combustion chamber it would be bad enough - 450C would flash the fuel before it was compressed..

Even if you factor in heatsoak - surely it would be neigh impossible to get Intake temps over 100c...

And if it is, then the intercooler is adding heat, not taking it away..

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I'm not suggesting that at all. As Tweak'e points out, normal temps entering the intercooler (that I've seen referred to) are somewhere between 200-300C.

The 550 is a hot bugger. The turbo sits at the top of the 'V' at the rear, right at the hottest area of the engine bay. Fresh air comes in from the air filter along the turbocharger intake where it does get some heatsoak - even in my car, I've seen variations of 6-8C from ambient. The air is then compressed which massively heats it up - and my concern is that because of the extra distance from the air filter to the turbocharger, the location of the turbocharger, and the inevitably long path back to the intercooler, that the intercooler's intake temperature is likely to be higher than we expected.

And that means - in my book - that Nissan (who are better engineers than I) ought to have considered this and used a suitable material in the construction of the intercooler, which I suspect they didn't.

A particular lack of foresight was also evident in the charge air hosing in the early 550s (that's the rubber hose between the turbocharger and the intercooler).

It's amazing that they still manage to pack the extra thousands into the price tag, while shipping the unit with components from The $2 Shop.

Would not a output temp of 2-300C near on melt the rubber piping? I can honestly say I've never seen IAT's, pre-intercooler any higher that 120c on a turbo car.. Similar for a Supercharged car... IAT's POST intercooler would then be around then 50C..

I can't imagine an stock intercooler being able to pull 200C outta the intake charge..

Anyway, Regardless, that's a really budget part that Nissan have put in there.. Ive heard of thin walled tubing before, but that takes the cake.

The highest i've seen on my ZD30 pre intercooler is about 175c. I'd guess the tube is thinner than the others and that is why it expanded.
http://www.youtube.com/watch?v=qb0sYkvHbLA
I'll go for a drive tomorrow and give it a flogging.

As previously suggested- straight out manufacturing fault. Should be a straight out warrante job.

Black_Outlaw said:

Would not a output temp of 2-300C near on melt the rubber piping? I can honestly say I've never seen IAT's, pre-intercooler any higher that 120c on a turbo car.. Similar for a Supercharged car... IAT's POST intercooler would then be around then 50C..

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no it won't melt it. its a poor conductor of heat and its being cooled by the air in the engine bay.

temps are related to boost pressure. there a few online calc where you can put in boost, turbo efficiency etc and it will tell you the theoretical heat output.
cuz is a truck mechanic and he has lots of problems with some of the 50psi+ boost engines blowing hoses off. the pipes/joiners have to be cleaned and fitted perfectly with good clamps.