Cool Running VVC 1.8 k series

[allan.guy]

I have an un-modded 1.8 VVC 165 K series which i  which is barely registering any water  temperature on the gauge when driving normally in these cooler/cold months. It does when left to tick over for a long time eventually hit over 80.  I have recently had silicone hoses fitted so airlocks are probably not the issue, it did this before and still does it after.  I do get some heat out of my heater but pretty much only when i stop and the car heats up.  I thought that this was just normal cold weather behaviour until I discussed this at a meet last night so I am now after some ideas to fix.

Is it the thermostat? if so which one do I buy 74, 82, 88?  or do i just do the QED mod if that is the right route again which temp? Or is it something else?

Any advice appreciated  thanks Allan

 

[john milner]

It takes my gauge on the coldest of days no more than 20 minutes to get to 80 and nearer to five minutes on a hot day. My heater works fine but cold weather does take a lot of heat away from the cars interior so apart from a warm left knee and bunch of keys I don't feel all of the benefit. You could try driving with a full hood for a few miles as it should get uncomfortably hot this time of year with the heater on. I think the standard thermostat is 82 as my temperature stays around this point.

A lot of people do complain about airlocks so that or a dodgy sender would be my best guesses.

[Jonathan Kay]

Reports of Ks running cold seem to have become more common. Some have resorted to radiator blinds.

When mine was rebuilt it was suggested that a lower rated thermostat was more suitable than the factory spec. But I don't know if VVCs are different...

I'd want to check that the current thermostat closes correctly... using a pan of water and a thermometer.

Jonathan 

[revilla]

My VVC used to run the water at 80°C under pretty much all conditions. I recently replaced the head, and while I was at did a light porting job, VVCBP270 exhaust cam and timed all the cams in precisely with offset dowels (and a lot of messing around!). It now goes like stink but struggles to warm up on cold days like yours, although not to the extent that it struggled to get off the bottom, just wants to sit at 70°C-ish (and that's both oil and water) on a cold day unless you push it. When you do push it, it goes back up to 80°C and sits there like before, but as soon as you back off it tends to drop off again. I'm pretty sure all the senders and gauges are reading correctly (or at least as they used to).

Cam timing can be dreadful on the VVC - I've just timed up three engines, none of them were even close to optimal and one of them had a 10° difference between the front and rear inlet cams and 17° retard overall. I think my engine is now rather better at turning petrol into work instead of heat than it used to be!

82°C thermostat is the usual choice. I doubt you've got airlocks but just check all the hoses get hot to the touch, particularly the bottom radiator return hose and the bypass hose to the heater valve. If they do you're circulating water properly. Airlocks up around the heater (highest point) tend to resist water flow round the bypass hose and so prevent the thermostat opening. Airlocks can happen in the thermostat housing in which case they effectively insulate the thermostat and again prevent it from opening (won't happen if you drill a 2mm hole in the TOP of the flange on the new thermostat, lots of info and pictures in the archives, also seems to lead to more stable temperatures without the thermal cycling that is so bad for the K Series head gaskets by keeping the radiator water moving and prevent it from completely chilling - at the expense of a slightly prolonged warmup time). Either way airlocks usually make it run hot.

Mine has an oil cooler with an 80°C thermostatic sandwich plate - it needed it before, after a good extended caning it was pushing the oil up towards 120°C which really wasn't healthy, but I think it's a bit overkill now. The oil thermostats work differently to water thermostats, after all you can't really shut the oil flow off when it's cold! So they just open a bypass that lets the oil route around the cooler when cold and most (but not all) of the oil goes round the easy route. You do still get some cooling though even when cold as there is still some flow through the cooler even with the thermostatic valve wide open.

Will see how it goes over the course of the year but I may have to look at ways of blanking some of the cooling off at colder times now - or just thrash it a bit harder!

[SM25T]

VVC here. I did the mod to the cooling hose layout as per article in LF September 2012. I have PDF Copy if anyone wants one. 82C thermostat. Runs at indicated 80C all day long ... Even when ambient above 40C