What's wrong with my VX?

[Pope1]

Guys, I'd appreciate any ideas, suggestions or insights please. Two issues, perhaps related?

1. What should the oil pressure gauge indicate when the engine is warm? On my car the oil pressure appears to be normal (about 70% across the scale) when the car is moving. However, at idle the pressure drops to just above the red segment on the left.

2. I've started getting a rumbling (bearing-like) noise from the engine which can be heard clearly at idle. Appears to be coming from the general vicinity of the supercharger/alternator. Engine still seems to run very well but the little red battery light on the dash is glowing so I was wondering/hoping if it might be the alternator rather than the supercharger or something else. The light is not solid red but it is more than the faint glow that always seemed to be standard at night with the lights on. The lights comes and goes but not in response to engine speed nor does it flicker. Gets a bit brighter, stays like that for a while, dims and so on. All of this driving at night with the lights on but turning the lights off does not appear to make much difference. Had to drive in traffic just now so engine temperature rose and the fan cut in several times as it is supposed to. Picked up a little speed (30-40 mph) and temp came down a bit but did not fall as much as I expected. Remained around the 50-55% mark.

If anyone can make anything of that collection of symptoms please squawk ASAP. Thanks.

Chris

[chrisc]

Both answers im afraid are highly dependent upon the condition of the electrics in the car :)

The dash light is par for the course, the oil pressure... well, youd have to check the connections before drawing any conclusions.

The noise you are hearing could be any one or more of the bearings on that side - when was the last time the cambelt tensioner was changed?

[Pope1]

I've been gradually overhauling the electrics over the past few months and generally they seem to be in good condition. I'd even managed to get rid of the usual faint red glow from the battery light a little while ago.

Yes the timing belt tensioner is another possibility. The last time that the car had major engine work was in 1995. However, it covered maybe 10,000 to 12,000 miles between 1995 and 1997 and was then laid up until January of this year. I've been using it a bit since then while trying to get all the bits and trim etc back on.

I've recently bought a complete set of belts and a tensioner and plan to change them all soon just because of their age and the climate here.

On a 'normal' Beta, what does the oil pressure gauge do? Can't remember what mine did before and the last car I had with an oil pressure gauge (Fiat Punto GT) the pressure remained at a fairly healthy level at idle.

[chrisc]

Well, I cant speak for any normal beta - is there such a thing?? but my 84 vx the oil pressure would be middle - high at startup and drop to the just before the red at hot idle, with it being marginally closer to the red if it was 'really hot' idle (sitting in traffic after a good long run). The engine in that car was sound enough, slightly worn rings on #3 and #4

My 85 however seems to feel that middle high on startup to just below middle when hot. I havent done any thorough tests on the condition of the engine, but it sounds and feels extremely healthy - like, factory fresh healthy :) (if only the rest of the car matched!)

[Pope1]

[quote="chrisc"]Well, I cant speak for any normal beta - is there such a thing?? quote]

Couldn't agree with you more about 'normal', :D hence the quotes.

Thanks for the feedback on the oil pressure. Consensus from the guys in the US is that the indicated pressure does drop significantly at idle with a warm/hot engine. Seems like you have a particularly health one there - hang on to it.

I'm going to check out the alternator as soon as I have time.

[Wallace]

I have heard that the oil pressure sender can develop a fault so it reads low when the oil is hot - leastways on a Monte anyway (the diaphram gets small holes in it - when the oil is hot/thin, it gets behind lowering the reading).

if in doubt, plumb in a mechanical one to the system just to check - it tops sleepless nights !

[Pope1]

Is it still possible to buy new sender units? Might be worth getting a spare and surely they can't be expensive, can they?

[Wallace]

Assuming its the electrical one - no - about 20 - 25 pounds UK rings a bell. But they are inaccurate - I was worried about low oil pressure on my car so just jury rigged a mechanical one to check. Took the car for a drive, oil pressure was fine so I took it off !

[Pope1]

Thanks. There are no other signs of oil pressure problems, I just wondered whether my gauge was behaving normally. I think I'll leave that side of things well alone for now on the basis of "if it ain't broke..."

[Paul C (Monte 3686)]

My car had similar very low readings after running for a while, and changing the sender (readily available, but cost 38 pounds!) chaged this dramaitcally. Having said that, once the oil is really hot, it goes down close to the red at idle - and I do have worn big-ends (can be heard on start from cold) that will be replaced this autumn.

Cheers
Paul C

[Pope1]

Here's the latest.

Checked the alternator in situ with belt disconnected. Turned freely with no sign of anything amiss.

Put belt back and went out in car. No sign of battery light. Cannot explain why that was glowing last night.

Began to wonder about the water pump only because I really don't want it to be the supercharger :-). Tried listening here and there with a piece of tubing and could hear nothing coming from the supercharger, the sound was lower down.

Tried disconnecting the alternator belt, which cannot actually be removed due to the supercharger belt, and soon after touching the water pump, coolant started dripping down. Ran engine for about a minute with the belt loose and it sounded WONDERFUL.

So the water pump seems to be the culprit which also explains why my car goes from normal to hot so quickly.

Thanks once again for your feedback guys.

Chris

[Pope1]

Earlier on I said that I could not figure why the battery light was glowing when the water pump seemed to the problem. Well after a little more thought it seems to me that since the water pump and the alternator are driven by the same belt, the bearing problem with the water pump could well have had an effect on the alternator. I suspect that I may have tightened the belt too much in the past which put undue stress on the pump bearings. After slackening and re-tensioning the belt today in order to test the alternator perhaps the drag from the pump was not as great as before???

Chris

[chrisc]

Sounds like it makes sense to me. Whilst youre changing out the water pump do the cambelt and tensioner anyway :)

[Wallace]

slightly off-topic - but I have saved money in the past by stripping an alternator and just replacing the bearings if it's noisy. you have to be a bit carefull you don't snap the brushes getting it appart - but the bearings themselves are just "standard" ones and go for about 5 pound each - cheepr than a "recon" one !

[Pope1]

ChrisC thanks for the reminder about the belt etc. I may as well get everything done at the same time including the supercharger belt and get it all over and done with. To be honest I've been putting it off as I'm dreading the whole belt changing exercise but it will have to be the end of next week as that is when I'm expecting my new water pump from the US.

Wallace thanks for the tip about the alternator bearing. Mine seems OK at the moment so I'm inclined to leave it and I do have a spare VX engine sitting in my garage. Maybe I'll check out the alternator and do any cleaning and refurbishing that is necessary on that just in case I need to do a swap one day.

Chris