Maxi overheating at speed

[theorganist]

I have a problem with my Maxi on which it ovetheats at speed!

 

I set out yesterday in the Maxi to go to Devon I set out with the oil level showing above maximum on the dipstick. I got on the M5 at Bromsgrove, by the time I reached the services at the M50 junction the temp gauge had reached the red. I pulled up in the services and water was coming out the overflow. Once it had cooled down I checked the oil and it had gone below minimum, that was just twenty miles at fifty to sixty mph!

 

I refilled with oil and topped the water up and drove back home mostly non motorway and the tempgauge sat mostly in the middle except when on the longer stretches of fast road. When I got home I checked oil and water and all was fin

 

I assume it is a sign the engine is very worn, it drives quite well.

 

Just wondered if anyone had any suggestions?

 

Thanks,

Pete

[dollywobbler]

Clogged radiator and/or silt in the block - both very possible if it spent a lot of time sitting around. With the engine up to temp but turned off, see if you can feel the face of the rad for any cold spots. Or the thermostat could be stuck in a slightly-open manner, so not enough coolant is going through the rad. I would have thought the first scenario is most likely.

[theorganist]

Thanks dw forgot to mention I flushed the radiator. Will test the thermostat. I wondered if it was linked to the oil usage?

 

Borrowed a car in the end to get to Devon so won't be able to do anything till Saturday.

[dollywobbler]

Possibly. If it's overheating, the oil will get thinner and thus find it even easier to escape than usual. Just thought that the other possibility is that the water pump is knackered. Also, flushing the rad might not have removed any really thick deposits. When I removed the thermostat on my Mk1 BX, the housing was like a mineral cave!

[Mr_Bo11ox]

I reckon that sounds like a clogged radiator too. However i would probably change the thermostat first just to be sure, it takes no time (as long as the studs don't snap LOLOL) and costs nowt.

[dollywobbler]

Ah yes, on that subject, I recommend at least loosening those studs with the engine at full operating temperature. A bit of heat works wonders. Did that job cold on our Mini and sure enough one of the buggers snapped. Since then, I've always tackled the job with the engine warm. Might be in my head but it feels better anyway!

[theorganist]

Thanks a lot guys. Will have a look at the weekend.

[e287yba]

My MG Maestro 1600 R-series does this - the engine is essentially the same as the E-series, but the transmission most definitely isn't .

 

Once the rad fan is on in slow traffic, it generally stays on - and it spits coolant out for fun if the coolant level is maintained properly, the loss of the best part of a litre on the first journey after topping up to "the mark" is normal (it then maintains this coolant level!). "They generally do that, Sir!" seems to be the general cry, and no-one knows why - but maintaining the coolant level at a very low level in the plastic expansion tank (not an option in a Maxi, admittedly ) stops the coolant overflowing when the engine gets near operating temperature. Coolant and oil remain seperate, so goodness knows what's going on...

 

I consider it a foible, and keep an eye on it .

[theorganist]

Going to take the thermostat out over the weekend and give it a run without it in.

 

It was the oil loss that confused me more, it does burn it but very slowly,suddenly a twenty mile jaunt at 50 to 60mph down the motorway and it seems to use a sump full!

[Rocket88]

If it's burning that much oil, there'd be plumes of blue smoke out of the back end...............what oil are you using, 20/50 sludge is best.

[theorganist]

Thats the strange thing there isnt a plume of smoke from the back, not than I have noticed! There was a small puff the other day when I reversed but thats all I have noticed.

 

It is 20/50 oil generally than I use.

[richardthestag]

what they ^^^ all said, blocked flow is the cheapest and most obvious thing to check for overheating at speed.

 

I might remove top and bottom rad hoses then run a hosepipe into the top of the rad and see how quick the water comes out of the bottom of it. My guess is that it wont really and that most of the water will overflow back out of the top hole.

 

You can try rad flush remedies but there is a fair chance that if blocked that badly then a recore is the only answer. I used Boston Rads in the past, they are very good.

 

Also when topping up you havent mixed antifreeze types, blue and pink/orange. If you do then it can "apparently" turn the coolant into something like wallpaper paste. - Not witnessed this but I am very careful to avoid mixing different types.

 

Oil issue is hopefully down to using the wrong stuff. I run older engines on gloopy fully mineral halfrauds 20/50. Rover v8 quite likes the mineral 15/40 in the blue plastic can from the afore mentioned establishment. like other said that sort of consumption out the exhaust should be pretty obvious.

 

I might get the engine warm and then in neutral/parked up give the engine some beans and check for car marking its territory

[theorganist]

Okay thanks all for the advice, will flush it again. Last time it flowed through and very little crud came out.

[freebird]

There is an old trick regarding flushing crud out of a radiator. Go down to your local Cost Cutter, or the like, and buy a couple of litre bottles of cheap Cola, poor it all into the rad, block the ends up and leave it overnight.

I always thought it was an Old wives tale but i tried it and it worked a treat. My Rad had been flushed through both ways and all ways and i thought Id cleaned it out good and proper, however, good old Cola ended up dislodging loads more crap.

Worth a try?

[Rocket88]

Washing powder has much the same effect...............

[dollywobbler]

Washing powder has much the same effect...............

 

I remember Car Mechanics doing that with a 200,000 mile Skoda Octavia. Just chucked the stuff into the coolant and drove it around for a bit. Certainly didn't do it any harm and did seem to improve things!

[RichardMoss]

Vinegar also supposedly does it too. I used a cupful of washing powder in my Jeep Cherokee's system and it did seem to remove a lot of gunge.

[keef]

Did Woody have the front grille blanked off when you had these problems Peter?