Trouble with Rover 25 Diesel after going through puddle

The thermal shock has shattered the ceramic (glass monolith) honeycomb in the catalytic converter blocking the exhaust. As a quick diagnostic, it may rattle on gentle rocking. You'll gain an insight into the problem from reading some of the tests they used to do on carbureted engines:

Sounds like the cat has cracked from the cold water and is now blocking the exhaust.

Tim..

Does Rover 25 Diesel have cat?

Worth checking the air filter - wet or clogged and fuel filter again moisture or clogged. Should be able to drain fuel filter and check for water quite easily.

PhilC

Yes, it has a cat fitted.

Trouble is that a defective or clogged MAF gives the same symptoms, I've had this fault and the best description is like she's driving in glue. New MAF cured all.

I've driven through a flood in a diesel 25 and never had the thermal shock issue as mentioned. Mind you, I did drive through keeping a good bow wake rather than those people who pussy foot through and wonder why they conk out half way through.

PDH

driving a diesel car through a puddle, can cause severe engine damage ( hydraulic lock) if water is sucked up through the air intake.

Hi, thanks for all your responses. I have given the car a little rocking, but didnt hear any rattling for anywhere. I have looked at the air filter and it is dry, only a little dirty. I'm not entirely sure where the MAF sensor is (will looks in haynes later) but is it likey that water would affect this?

The problem seemed better this morning, my acceleration was not perfect, but certainly much better than before, yet this afternoon it was back to 'like driving through glue'

Oliver

You have two sensors on the L series that can go futt. The MAF (manifold airflow) is fitted inline with the 2 inch air intake frm the filter box to the turbo inlet and can be identified by a torx secured 4 wire plug. The second sensor, the MAP (manifold absolute pressure) and incidentally the one that went futt for me, is secured to the A frame bulkhead and has a vacuum hose running to it which is prone to getting blocked due to its small bore size. The wiring plug to this is located on the underside and is secured by a single bolt to the bulkhead. I was unlucky, the hose was OK, the sensor was out of range and the ECU eventually went into limp home mode and reduced the availale power hence the glue drive.

I would suggest that you carefully remove the MAF sensor first and check that it is clean, then go for the MAP sensor and check that the vacuum hose to it is not leaking or blocked. Both faults will NOT show up on a ECU reader until they totally go out of tolerance but the performance of the car can go overnight. Only way to test is by substitution I'm afraid and both sensors are not cheap. If you want to exonerate the CAT, you can replace it with a straight section of pipe to test if the CAT has collapsed but I suspect that your woes are in the engine bay and the sensors.

PDH

You have two sensors on the L series that can go futt. The MAF (manifold airflow) is fitted inline with the 2 inch air intake frm the filter box to the turbo inlet and can be identified by a torx secured 4 wire plug. The second sensor, the MAP (manifold absolute pressure) and incidentally the one that went futt for me, is secured to the A frame bulkhead and has a vacuum hose running to it which is prone to getting blocked due to its small bore size. The wiring plug to this is located on the underside and is secured by a single bolt to the bulkhead. I was unlucky, the hose was OK, the sensor was out of range and the ECU eventually went into limp home mode and reduced the availale power hence the glue drive.

I would suggest that you carefully remove the MAF sensor first and check that it is clean, then go for the MAP sensor and check that the vacuum hose to it is not leaking or blocked. Both faults will NOT show up on a ECU reader until they totally go out of tolerance but the performance of the car can go overnight. Only way to test is by substitution I'm afraid and both sensors are not cheap. If you want to exonerate the CAT, you can replace it with a straight section of pipe to test if the CAT has collapsed but I suspect that your woes are in the engine bay and the sensors.

PDH

Never driven a diesel to be honest; but why the hell are obvious items such as puddles not catered for by the now defunct British car-maker? One word springs to mind. It begins with retard.

I think puddle is being too liberal and the wrong description. I have taken a 25 diesel through at least a foot and a half of water with no ill effects. The trick is to keep going at a steady rate and let the bow wave keep the engine bay clear. You stop or slow down too much and that's the end of it.

PDH

It's not just Rovers. My wife effectively scrapped the engine on a ZX - OK, she went through a ford in flood, but investigation showed that the air intake scoop was behind the front bumper, and I could imagine the same happening with a deep puddle such as some I've seen in the last week!