Handling? Economy? The MG ZS Diesel - A Hidden Gem. My Ownership Story.

Posted by Mat Price on

Finding a car that's both fun and economical is a bit of a challenge, to say the least.

Before I had my MG ZS diesel I had an utterly fantastic Rover 620ti (1999, lovely condition) which I'd spent the summer driving like a lunatic at great expense. Now with little cash and requiring a sensible, economical car for my new job I turned to the MG 'Z' diesel range.

At first I considered the ZR - a fun, nippy little motor with lots of power on tap (mainly due to the weight of the vehicle) and exceptionally good looks. The model I viewed was in Trophy Blue, in marvelous condition and a total steal at just £1,495 (bearing in mind this was 2009). Problems began upon test-driving the car; I just couldn't get comfy due to my large build and 6'3" height. So, despite all of the positives, onto the next item.

I spotted a dealer who had both an MG ZT-T CDTi and an MG ZS diesel for sale over in Stockport, and a short phonecall later I was on my way to the Safe Store lockup outside which the cars were located. I had a quick chat with the dealer who seemed to know relatively little about the cars, instead handing me keys and directing me towards the service history located in the glovebox of each vehicle.

I started with the ZT-T CDTi. A well built and specified 2002 model in silver, she had full service history detailing a grueling battle of money thrown between the clutch hydraulics, ABS system and wheel bearings. Not letting this put me off, I took the vehicle for a quick spin to discover an extremely heavy clutch and virtually no low-down performance (common MAF sensor issue). All features of the car worked well, including the fantastic Xenon headlights and auto-wipers.

Next, the ZS diesel. I'd never really given the ZS much thought until this point, which is rather odd given the fact my first Rover was a 1997 416i. I loved that car, and when sat in the ZS I could feel the DNA of the 400 was still present. I liked the way the 'ye olde' feel of the 400 had been merged with a more modern interior design - the car still felt welcoming, yet modern enough to turn up a friends house without hearing 'Grandad's come to visit!' screeched from the worried family members within.

Boot space was good, of course not a patch on the ZT-T but very useable for a mid-size hatchback. A test drive confirmed my thoughts on this being a good example of a much under-appreciated car, to the point of agreeing a sale there and then. I headed home looking forward to bringing the ZS back the next day.


First impressions, faults and thoughts

As we all know, no foray into Rover ownership would be complete without some form of drama.

You could take the hurried insurance telephone call - during which the operative mistakenly entered the car as a ZS180 producing a quote of over £3,000, you could take the faulty fuel gauge - causing me to literally splutter into a fuel station and have to use the starter motor to finish the limp to the pumps, or you could take the myriad of other small issues you can have with any 2nd hand vehicle... namely speeds 1 and 2 on the heater not working, a sticky ignition barrel switch, 2 of the 4 electric windows being inoperative, the cambelts having never being changed despite being 6 years old, and most annoyingly a rather large amount of clutch judder. Onwards and upwards, however!

In all honesty, sorting out the majority of issues with this car was a painfree and relatively inexpensive experience. Speeds 1 and 2 on the heater not working is an easy fix (new resistors to be fitted to the heater resistor pack, a kit for which I now sell in this very Shop), a cambelt change although daunting is a surprisingly logical and relatively straightforward experience, and the window mechanisms simply needed a little bending back to shape (plus a liberal greasing!).

Here she is, around 2 weeks after purchase:

What's it like to drive and own?

I was genuinely surprised how little money is needed to run such a lovely car. I enjoyed every second of ownership, despite (as you will read) having some rather large bills towards the end of our time together. Still, averaged out over the time I owned the car, the bills paled into insignificance when you consider I did around 24,000 miles per year.

Driving the ZS felt so good it should be fattening - very 'chuckable' around bends, yet fairly relaxed (for a car with hard suspension) on long journeys. I traveled from the tip of Scotland to Land's End in this ZS, and there wasn't a time I didn't enjoy the journey. When you factor in the 55MPG+ on long steady cruises, it's hard not to fall in love with such a well-rounded vehicle.

Parts are cheap - back then I ordered from my local 'Partco' however I now sell all items needed for basic ZS maintenance in my Shop. Service kits for the diesel variant are £15.99, and considering this is a once-every-15000-miles affair you won't spend too much of your hard earned keeping a ZS diesel in good shape.

Mechanical issues - I didn't quite get away with a 100% reliability record...
While the ZS was cheap to run on the grand scheme of things, it did 'spit it's dummy out' on occasion.

The most memorable of these was when the clutch release arm seized solid in the gearbox housing, leading to a catastrophic clutch failure and some rather impressive photographs of such. 

In the weeks preceding the incident, I noticed the ever-present clutch judder getting worse. It's not hard to make the trim in the ZS diesel rattle, however every take-off from standstill felt like a battle between the laws of Physics and the clips holding the interior together!

On the night the failure occurred, I was picking up a friend from the middle of Preston city centre. She had been out for a couple of 'chocolate milkshakes', and once I had bundled her and a couple of friends into the ZS we set off for home. Around 10 minutes into the journey I accelerated up to 30MPH, and when changing into 4th the clutch pedal remained on the floor. This was followed by a total loss of drive - I could rev the engine freely in all gears.

I coasted to a rather unceremonious stop, and called my good friends at the RAC (who probably have lots of happy memories of the many breakdowns in my previous 620ti). The mechanic deployed to the scene reached my conclusion - total clutch failure. Once I'd been towed home I did a little homework, and found the sticky release arm subject discussed in detail (also noting the symptoms and possible following failure of the clutch).

When removing the gearbox to access the clutch assembly, I was greeted with this:

Oops! The metal components all showed signs of excessive heating, and the friction material was heavily pitted. Luckily the flywheel was undamaged.

New clutch (available in this Shop):

I also replaced the gearbox oil seals (available in the Shop) as they tend to wear with age, and the last thing I need is another problem.

Finally, I removed the seized clutch release arm, cleaned it up, regreased it and refitted.


Upon refitting the gearbox, it was clear the problem with my clutch certainly wasn't a new one. The new clutch was wonderfully light - it truly transformed the car.

Having a new clutch also opened another door I'd been wanting to explore - tuning the L Series diesel engine.

Modification - My quest for power

The L Series is an incredibly basic and agricultural diesel engine - despite many attempts during its life Rover never managed to quite shake the 'tractor' feel. The benefit of an older, tried and tested design is of course longevity and strength. The L Series is known for it's resistance to abuse, the build of the engine is a solid design which is capable of dealing with much more power than originally intended.

The weak point in modifying the L Series is usually the clutch - they can only deal with around 250 lb/ft of torque reliably from new. Of course as the clutch wears, this will decrease slightly due to less clamping load on the driven plate. My shiny new clutch was the perfect excuse to up the power and really see what the ZS is capable of.

SDi Injectors should be the first port of call for any 25/45/ZR/ZS diesel on the quest for more power. It's a pretty crude modification - the SDi injectors open at 200 bar rather than the 210 bar of the later injectors. You can find SDi injectors in any 200/400/600 diesel. Gains of around 20-30BHP are normal.

Next, a decat. Removing the catalytic converter on a diesel vehicle will NOT fail an MOT, as emissions are not measured in the same way as their petrol counterparts. Simply remove the catalytic converter and use a large masonary drill or chisel to gut the cat. Collect the honeycomb that you remove - it's worth a fair amount due to the platinum and other precious metal content. I also had a Powerflow stainless steel catback exhaust fitted to replace the corroded mild steel item.

A remap does help the diesels - it brings in the power further down the rev range, meaning full boost and thus power are reached sooner. With a limited rev range, having the power lower down can only be a good thing!

Finally, make sure the engine is getting enough air - a high-performance air filter and a boost increase to 19psi will help you achieve top power.

The ZS had all of the above done one step at a time, and I can't speak highly enough of the way it transformed the car. Wheelspin in 3rd gear (in the dry!) was entirely possible.

Head trouble on an L Series? Surely not!

As we all know, the K Series is the Rover engine with an infamous (and somewhat undeserved) appetite for head gaskets. While the later L Series engines do occasionally have a head gasket failure (usually from cylinder to water jacket), it's not common and certainly not something that should worry the average owner.

The story of my L Series cylinder head nightmare began on a cold February morning - I'd just started my drive to work and noticed the temperature creeping up past the half-way mark. Upon stopping, I could distinctly smell coolant. Upon opening the bonnet, I was presented with this sight:

Water appeared to be welling up around the number 4 injector. After filling up, I had a rather uneventful drive to work, however noted that I had been losing coolant steadily the whole way there (around 500ml for a 10 mile journey) and the head was covered in fresh coolant staining.

I believe the cause of this was a sudden cold snap of weather, during which time my antifreeze concentration wasn't quite high enough to stop the coolant freezing. I let the engine thaw out fully before attempting to start, however it seems I didn't get away scot-free!

The ZS ran fine like this for several months, until one day I lost power, the temperature shot into the red and I noticed a lot of steam from under the bonnet. I happened to be in the Scottish Highlands at this point, luckily with lots of water in the boot thanks to the leak from around injector #4.

Coolant had erupted from the expansion tank with considerable force, and was all over the engine bay. I waiting for everything to cool down, refilled, and set off again. When passing a slow-moving vehicle the same thing happened - it seemed whenever load was placed on the engine the cooling system would overflow with quite some force.
I tried various parts - new cooling system (pretty much everything!) and even the dreaded K Seal to no effect.

No time to ponder though - at least this apparent head gasket failure would give me chance to fit a known good second-hand head to my ZS. I set about ordering all the parts needed (I wish I'd had this Shop back then!) and finding a good cylinder head.

In the meantime I still needed a car, so found the most mechanically sound yet cheap Rover 400 I could find. A 416i in Flame Red, no less! A free-revving K Series was fun, so I spent a lot of my driving time like this:

My victim was a lovely blue Rover 400 diesel in a local yard - with low miles and a clean engine bay it seemed a safe bet. The later (post-99) cylinder heads seem somewhat weaker than the early items, so when replacing a head I will always try to find a head as early as possible.
Here's the donor:

Victory - the head is off!

My friend also managed to absolutely destroy the engine fitted to his Rover 620 SLDi at around the same time, an impressive feat as I'm sure you'll agree. He actually melted 2 pistons, caused by mis-fuelling (attempting to 'cut' vegetable oil with an unsuitable product) and excessive cylinder temperatures. The breakup of the ring lands of the 2 pistons was very similar to the damage observed when excessive boost is used in a T Series engine.

For moral support and ease of tool-sharing, we popped the cars next to each other in my parent's garden and set about getting them back in tip-top shape:

Thankfully, a head gasket change on an L Series is rather easy. A single cam non-crossflow head, good access and fairly logical sensor placement mean the job didn't take too long at all, and before I knew it the ZS was back on the road.

I also found out my partner and I were expecting our first child around this time. While the ZS is very roomy for a small-ish hatchback, I couldn't shake the feeling that a Rover 75 would be a better bet for family life - in particular a Tourer.

I spent a long time deciding on the best move car-wise, and in the end I decided to opt for a 75 when finances allowed. Unfortunately my plans would soon be changed, as a learner driver decided they'd like to pull across my path at a busy junction.

Not one for having British cars leave the road without a fight, I set about preparing for the repairs. My insurance company wrote the vehicle off as a Cat C, however I managed to buy it back for £150! This was 10% of the £1500 payout.

I needed a car, and absolutely despised the hire car I was given while the claim was finalised. I bought a temporary runaround - a lovely MG ZT190+ :

After a few weeks of part hunting, I had a new bumper, headlight and crash bar ready to be fitted. 4 hours later and the ZS was back on the road, and aside from a small crumple in the bonnet was in excellent shape.

I realised this would be a good time to exit ZS ownership with a profit, so sold her to a friend. She's still running OK, and is currently having a rest while a few suspension parts are refreshed.

I loved owning this ZS - a fantastic car. At times my patience was tested, however I don't think I'll own another car quite as memorable as this one.


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  • Enjoyed reading that so much so that I’m off to see a ZS 2.0td today..

    Jim Gapp on

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