[wise]

Hi
I’ve been searching for an answer to my problem with very little clarity of what the problem could be, so I’ll try and explain. I have a Traffic 2015 138k 1.6 dci with a very peculiar overheating problem, When the engine is up to temperature the coolant is pressurised in the reservoir and leaks out from the filler cap and the heater blows cold. Replaced filler cap, auxiliary belt, the belt driven water pump, the thermostat, and the EGR electronic valve all for new, also had the 2nd EGR exhaust cooler bypassed at the back of the engine on the cooling side to eliminate a faulty cooler leaking emissions into the coolant system. Replaced coolant hoses for new. I’ve also had a combustion leak test done with a BT-500 Block tester. There are an additional 2 electronic water pumps, one under the radiator/engine and one under the battery housing. I’ve tested the voltage at the termination point at both of the pumps and they both have 12 volts dc. I have tried using the additive "Steel Seal Gasket Engine Block Repair" twice but with no positive results. When the van has been driven for at least 10 miles or so the engine light comes on saying "STOP" engine failure! it seems to be not circulating the coolant due to the pressure build up and or the cylinder head has gone, or it has a porous block also to note coolant is not being lost, only when the overheating occurs. No oil in the coolant, and no coolant in the oil. To note it’s the R9M450 engine. I really don’t want to take the head off just to find it’s not the head, only other option is the radiator blocked or perhaps a blockage in the block it’s self. I also removed the thermostat internals, I need to replace these as a hot water test proves it works fine, you may think why have I changed half the things above but Anti pollution check on the dash was the reason for the EGR which was seized in and had to be drilled out! And now it’s a merging that it’s a Bosch MAP Intake Manifold Boost Air Pressure Sensor which causes this so that’s the next thing to change, but if anyone knows the fix I’m all ears!

Hello Mat,I have renault traffic 1.6 same issue I have please let me know did you sorted out what is the issue
Thank you

 

[steve inv.eng]

Quick reply to those of you not getting heat in the cab, particularly on mine the euro6 biturbo, There are two electric accessory pumps on a circuit of the coolant system these circulate coolant between the low pressure egr cooler and through the heater matrix and then back into the outer circuit... I had power at the terminals and using a power probe had the pumps working, the problem I had the terminals on the loom had been spread and where loose on the component pins and so weren't working, I'm also suspecting I have a partially blocked heater matrix... Hope this helps some of you..

 

[steve inv.eng]

Also another update on the heater issue the egr cooler on mine I had to replace as it had become blocked with oil and carbon from the turbos failing... when the cooler becomes blocked the actuator flap to control gas flow comes into contact with this carbon and I had wear on the flap and hole which it rotates with in and had hot gas escaping which would also result in a loss of heat transfer to coolant, unfortunately with this problem I believe this is the fault that leads to head warpage as the flap opens to allow egr hot gas to pass through a gallery in the end of the cylinder head that hasn't been cooled effectively.
Should be 200c cooled 600/800c not cooled
This creates a hot part of the cylinder head..
Resulting in warpage that will require cylinder head pressure check and skim...
Hope this helps

 

[wise]

Thank You Steve I replaced EGR last year

 

[John J]

Interesting thread.

@steve inv.eng I'm puzzled why, if it was exhaust gasses pressurising the system due to fail(ING) head gasket, why wasn't this picked up through detecting exhaust gasses in coolant?

I'm assuming your failing turbo was leaking oil into inlet gasses and causing the carbon build up your referring to? I guess oil vapour from crankcase venting would do the same i.e. be a source of carbon build up.

Surely if EGR cooling tube is blocked by carbon, that reduces gas recirc back to engine. As I understand it, the gas recirc is used to reduce combustion temperatures in the cylinder by reducing the oxygen in the cylinder and thus reduces NO2 generation.

So if EGR cooler blocked, no exhaust feedback to combustion process leading to higher cylinder temps and probable cause for HG failing. I guess similar effect as fitting EGR blanking plate.

I don't understand why a blocked EGR coolant tube would cause "loss of heat transfer to coolant." Perhaps you could explain? Sure, blocked coolant pipes to the EGR coolant tube would.

My interest here with respect to improving my understanding in this area better to ensure my replacement Espace engine (3.0dci) doesn't suffer from overheating (which is common) and displays many similar symptoms as on here.

I'm thinking it may be best to replace crankcase venting into the inlet circuit with an oil catch can and blocking the crankcase vent to the air inlet circuit.

I know a number of people have issues with EGRs coking up. Perhaps oil vapour in crankcase vent is root cause and which can lead to localised cylinder overheating ultimately leading to HG failure.

 

[steve inv.eng]

Hi John
On the vivaro bi turbo there is a low pressure egr cooler that cools the gas before it passes through the end of the cylinder head before it then enters a dedicated port to the egr valve inside the inlet manifold, the design of the low pressure cooler allows for its body where the gases should flow past a heat exchange area becomes full with oil and carbon to fill that part but the actuator flap and arm keep a clear path through its continued operation, this causes excessive wear on the flap valve particularly the aluminium housing pivot point the actuator arm wears and results in it neither fully opening or closing.. there is sufficient room for hot gases to pass and cause potential faults..

On the subject of egr blanking..
This type of engine as far as I understand is constantly reburning cooled egr gas 20% the reduction in No2 is further improved by only having to put 80% fresh fuel air mix..
The egr system also operates under any form of deceleration..
I actually put a catch can in my old high mileage vivaro as that had excessive crankcase pressure..
With the newer systems euro 5/6 there are all sorts of sensors detecting pressures everywhere even a catch can would have to still be connected back to the intake side and not vented to atmosphere..
Hope this helps some..

Crankcase pressure on mine is absolutely fine no issue

 

[John J]

Thanks for the clarification.

My engine is Euro 3 I believe which is much simpler, but I understand has thermal issues.

 

[chrisWl]

Have the same problem with 2015 R9M450. Went in for pollution and injector warning and have been told by the Renault garage the coolant level is mysteriously dropping and it could be head gasket. But they can’t be sure. And they said it’s not worth looking and it’s for scrap basically.

 

[cf095024]

Did anyone manage to resolve this issue as i suspect my van is starting to show similar symptoms. Thanks

 

[cf095024]

Did anyone manage to resolve this issue as i suspect my van is starting to show similar symptoms. Thanks

@Mat928 did you have any luck with yours?

 

[Ryanseca]

Renault trafic 2018. At idle no overheating, drive for a bit then overheating and water coming out expansion bottle. No heating out of blower either and one side of radiator cold. The electric pump at the back of engine was suspected to me to be at fault or blocked as no water coming out with engine running feeding the matrix. A few days in solved, put in radiator flush and flushed the system at the matrix pipes both ways with a small 12v pump with a tank of clean water, all sorts of debris came out both ways and out water bottle also . Filled fresh water, heaters working blowing nice and hot radiator hot. Diagnostic machine showing temperature sitting at a steady 85 -90 degrees while driving. Hope this helps someone as there doesn't seem to be anyone with a fix online.

 

[bradwright9797]

I mate did you ever solve the problem. Id be really greatful if you could reply with what you did. kind regards Brad