Hi all, my 06 1.8 has developed a rattle. It has 86k on the clock and has been well maintained. It starts up fine with no noises, but after about a minute or so there is an intermittent rattle, particularly when running just above idle, and at low revs.Â
I did some digging around through forums etc and found that a few people had described similar problems, which had been fixed by changing the tensioner and idle pulleys as the bearings can wear out. So to test the theory I backed off the tensioner and removed the serpentine belt, then started the engine again keeping all fingers and toes crossed. Sadly the rattle was still present, so now I am thinking worst case scenario that the big end is kaput - which from what I have seen involved replacing the engine at a cost of about 2k - which will pretty much write my car off.
I thought initially while driving that the noise was coming from beneath the car and could have been the exhaust, but having now listened with the bonnet up it is apparent that it is coming from the engine and sounds like it is coming from the top end. Best way I can describe it is it sounds like a diesel engine for a few seconds then runs normally for a while and starts again etc.
My other car - 1.8 zafira used to have a similar noise on startup and that was caused by a blocked mesh on a solenoid that controls the vvt system and starves the top of the engine of oil. I am not as familiar with this engine but have been trying to work out if there are any other basic checks I could do before I have to take it to a specialist for confirmation.
Only other things I can think of doing are to inspect the exhaust manifold, or change the oil and flush the engine - does anyone think there would be any value in doing this? In terms of the oil level, it is very difficult if not impossible to read the dipstick. The oil pressure gauge in the dash shows between 50 and 80% when the engine is running so I assume there is sufficient oil in it, however I am aware that I need to get a new version of the dipstick to be sure, as it’s a job to see if mine is overfull or empty. I’m not sure if there is a possibility on this engine of the top of the engine being starved of oil and that could be causing the rattle etc.
Any thoughts or advice would be very much appreciated - thanks in advance.
Quite a few say they have difficulty reading the dipstick on the Mk3, yes it can be a pain but I find it ok to read. Dip the oil when the engine is cold, preferably leave overnight, check in the morning before starting. I wouldn’t assume there’s enough oil in it from the oil gauge The one thing is for sure, low oil level will kill the Mk3 engines, I read only the other day the 1.8 is more prone, why I have no idea maybe it was idle forum talk??
I’m no expert but it doesn’t sound (I can’t hear it either) that your engine sounds terminal, surely the noise would be consistant if it was lack of oil?
I think the 1.8 does not have VVT. People forget the car does have a timing chain that can wear. Perhaps an easier solution would be a second hand unit from Ebay. Otherwise the car would only be worth ÂŁ1000 in its current state. The video is a Mazda 3 to show the sound of a timing chain problem.
Sadly the oil pressure gauge means nothing other than there is “some” pressure. It is driven by the ECU ( PCM ) and reads dependent on rpm and I think, to a degree, engine temperature. It is not a true pressure reading. An engine flush and oil change never does any harm so try the easy things first. When was it last changed? Good luck. D
just a thought, if you do decide to do an oil change, measure the amount of oil that comes out, that way you’ll know if it was low.Â
A top end rattle might not be terminal - these engines tend to suffer bottom end knock if the oil drops too low, as I understand it. Might be worth investing in an inexpensive stethoscope to try and find exactly where the noise is emanating from.
Many thanks all for your replies. Today I reassembled the old tensioner and serpentine belt.Â
I also picked up an engine flush, oil filter and oil.Â
Before starting the service I decided to try and check the oil level again but could not get an accurate reading (or any reading) from the dipstick. I have never had a low oil warning light on the dash and as the gauge on the dash was showing 75% I never really considered that the car might be running low on oil. Also I was aware of the dipstick reading issue on this model. That said, from the cars history it was getting on for 9 months since the last service and the oil that I could see was quite dark in colour so found it strange that it was not visible on the middle part of the dipstick.
I decided to put some spare oil in I had left from a service on my other car which has the same viscosity to see if it bought up a reading on the dipstick. I was worried about overfilling initially but then figured that as I had planned to drain it all out anyway I could not do too much harm.
I gradually added approx. 1 litre, which to begin with made no difference to the reading. IÂ let it settle and to my surprise it seemed to then be showing a small amount of oil on the end of the dipstick so I added a bit more and started the engine, ran it for about 15 minutes and no more rattle so far!
I can only assume that the engine oil was really low and causing it to intermittently starve the top end of oil causing the rattle I’m just hoping now that no lasting damage has been done to the engine as a result of this.
I am going to do the oil service tomorrow and will also check the spark plugs and air filter (replace as necessary) and keeping my fingers crossed that this issue is rectified. I was starting to think I may end up having to write it off if the big end was kaput.
In every other car I have owned (including the mk1 eunos I had) have shown a low oil warning light with plenty of time before it was at a level that could damage the engine. Not sure if the sensor or sender for the light on this car is not up to the job, but will be ordering a new dipstick and checking it weekly going forward, assuming the engine is undamaged!
A retired mech I used to know had a long screwdriver with I wooden handle he would stick the handle to his ear and the steel on the engine and move it around to pin point a rattle
It always seemed to work for him but a word of warning he had a terrible cauliflower ear !!
If you have an oil warning light it is a low pressure warning, not a low level warning. If the oil light comes on while engine is running you should turn off the engine immediately as you have lost pressure. Using the oil light as a warning of low oil level is courting with disaster. Your MX5 has hydraulic tappets so it may be them that are rattling. Running any engine with oil low enough for tappets to rattle is pretty bad.
It sounds like your oil level was so low it wasn’t even touching the bottom of the dipstick. Having read some of the horror stories on here about how sensitive the mk3 mx5 engines are, especially the 1.8, and that they have to be kept at ( or even above ) the max level, I do hope you have got away with this, and an oil change sorts your problem out.
After the oil change I would recommend you check the oil level on a weekly basis as all that oil must have gone somewhere. How many miles has the car done since the service 9 months ago?
Anyway, good luck and lets hope all is now well.
D
Well, I haven’t owned the car long. I bought it off a friend and colleague who sold it to me at a good price, because they had bought a car on finance which they needed due to ill parents and needing something more practical to get a wheelchair in boot etc. They also mentioned the recent rattle which I knew about when I bought it, but they didn’t have time or money to investigate.
I did a bit of research before buying it and thought it was worth a gamble because the symptoms fitted with a noisey tensioner. Also over the past 18 months the car has had a new exhaust at a cost of ÂŁ600 , new tyres, new battery, new brakes etc, all with invoices. They said they paid someone to do an oil change at the time of the MOT in March.
My guess is that the oil changer didn’t put sufficient oil in, as it’s only done about 4k since then and I’ve been under the car and can’t see any signs of a leak.
Anyway, I have done an engine flush and oil change / replaced oil filter and the engine now seems to be running lovely and quiet, no more rattling as yet but am going to run it for a while and time will tell. It is only really a weekend car as not very practical as my daily driver which I use for my job. Â
I will be checking the oil level weekly though going forward with the dipstick.
Thanks all for your inputs, this forum is ace and loving being back behind the wheel of an mx5, my daily driver is a people carrier which doesn’t put a grin on my face like the mx5 doesÂ
Sounds like you have been lucky and got away with itÂ
These engines can use oil, up to half a litre per 1000 miles has been noted, so if the oil has not been checked since the oil change, it could have used a couple of litres.Â