Maybe Air In The Cooling System...

[chocolate_o_brian 0]

I'll try explain this as best I can. My Pug (for some reason) seems to have been running without a thermostat since I bought her, as I have never needed to look. Anyways, by chance noticed it didn't have one, and today have finally managed to fit one after delivery was delayed. The same time I changed the coolant hose which has the 2 oil breather pipes circulating it. Great I thought, it will warm up to temp quicker and I'll get a better drive, more mpg etc.

 

I lost about 2.5 litres of coolant faffing about, which was replaced like for like. Ran the engine while topping up via the expansion tank. Seemed well. Took a few mins to reach a good temp and I thought all was good. So anywho, coming home in the snow (on mainly 30/40 roads) the engine seemed to be sat just above 3/6 bars. Ne worries, so I put the fans on to cool it a little. Sat in traffic and the temp didn't really rise but it didn't cool either with the twin fans on (these are run via manual switch).

 

I took it easy home and after having the fans on 5 mins, the temp was still 3/6 bars. Pre-thermostat, the temp never seemed to get any higher than 2/3 bars, and then if required the fans would cool nicely. So switched the engine off and ran the fans for 60 secs. This helped cool it, but it got me thinking all sorts.

 

Whats it gonna be like in warm temps?

Is it healthy to have the fans on so much?

Do I have air lock etc?

 

So any advice would be greatly appreciated. When I recently had the fueling done, the mechanic tested the coolant with the gizmo that has colour changing fluid in it. All was well then. I'm hoping its air lock or something other than a headgasket - good god lol.

[mickie 3]

been ages since i last seen the 205 clocks, but with a thermostat in the car once warm always stays around 90c, it shouldnt really drop from that, only go up from it, the fan will kick in to stop that tho..

 

to get rid of air locks, run the heaters in the car full, letting the engine idle with the expansion bottle cap loose, letting the rad fans kick in around 3 times normally, maybe a bit tricky with your set up but this should clear the engine of airlocks

[GLPoomobile 958]

I'll be honest, I only skim read your post (wife is nattering). But think it's because you had no thermostat before so coolant was always flowing through the radiator and therefore always affected by airflow. Now you have athermostat, the radiator is not used until the coolant goes above the temp of the thermostat. So if the temp is below this, and the radiator is not being used, then it stands to reason that the fans will not make a difference. The temp it's sitting at on the dial is probably the temp that the thermostat is rated to.

[chocolate_o_brian 0]

Ok thanks guys. In the past when the coolant temp has hit 3 nearly 4 bars, thats when I hit the fan switch, as its a manual one I have. This happened in standstill traffic, never on the roads. I just find myself constantly looking over at the water temp now as I'm uneasy anytime it drifts over 3/6 bars.

 

Wouldn't be so bad if it had automatic fans, but the wiring would need a overhaul for that - above my capabilities, but something planned in the future.

 

Is it safe to leave it at 3 bars and then switch the engine off at that temp? I remember before I once forgot to flick the fans on and switched the engine off at 4/6 bars! Lost 2 litres of coolant out the overflow pipe lol. Felt a tw*t that day! Has worried me ever since.

[GLPoomobile 958]

I'm used to having my temp gauge quite high in traffic. Can't remember bar wise, but you're saying 3 out of 6 bars, so that's half way. Mine (in any 205 I've had) has always sat around the mark before the max point in traffic.

[2-Pugs 57]

Just to second what GLP said. I think before, your car was running too cool, now with the working 'stat it sounds correct I had a similiar problem with my other car (Citroen Xsara VTR) when the thermostat jammed open, and it didn't warm up at all even after driving for several miles.

Edited February 1, 2009 by 2-Pugs

[chocolate_o_brian 0]

I'm used to having my temp gauge quite high in traffic. Can't remember bar wise, but you're saying 3 out of 6 bars, so that's half way. Mine (in any 205 I've had) has always sat around the mark before the max point in traffic.

 

Well my thinking (having experienced loosing coolant from the overflow hose), is that the water temp needs to be about 3/6 bars or lower when switching off the engine. Otherwise I'd risk loosing coolant again due to overheating. So I use the halfway mark (3/6 bars on water temp) as a guide to keep the water temp at. Anything lower is fine, warming up etc, but anything over and I generally flick the fans on.

 

I'm gonna try for airlock tomorrow morning when the engine is warm, see if that helps. Also check the heater is a constant warm too. If not, all I can assume is the rads suddenly got blocked, or the new thermostat I put on today has a high temp setting?

[chocolate_o_brian 0]

Just to second what GLP said. I think before, your car was running too cool, now with the working 'stat it sounds correct I had a similiar problem with my other car (Citroen Xsara VTR) when the thermostat jammed open, and it didn't warm up at all even after driving for several miles.

 

Yeah, it just seems to be a very fine line on the temp gauge betwen running at normal temp (3 out of 6 bars), and seeming to be overheating (4/6 bars). As mentioned in a previous post, when I turned off my engine once at 4/6 bars, it spat coolant out everywhere

 

Hopefully I can get a clued up electrical mate to wire me in the fans so they kick in atomatically again. It did my head in to keep looking at the temp gauge.

[GLPoomobile 958]

I think something must have been wrong for it to spit it's coolant that one time. Think about it. When you turn off the engine it's not getting any hotter, so why would it spit it out then, and not when running? Furthermore, I'm used to switching off a hot engine (London traffic), and the fans will keep running for a minute or so afterwards, but with the engine off the fans are only cooling the radiator (where the fan temp switch is located). So the fans cool the coolant in the radiator, the temp drops, and the fans stop. It has no effect on the temp of the coolant in the rest of the system, which as I said, is not getting any hotter.

[chocolate_o_brian 0]

I think something must have been wrong for it to spit it's coolant that one time. Think about it. When you turn off the engine it's not getting any hotter, so why would it spit it out then, and not when running? Furthermore, I'm used to switching off a hot engine (London traffic), and the fans will keep running for a minute or so afterwards, but with the engine off the fans are only cooling the radiator (where the fan temp switch is located). So the fans cool the coolant in the radiator, the temp drops, and the fans stop. It has no effect on the temp of the coolant in the rest of the system, which as I said, is not getting any hotter.

 

All I can think of that particular time was because the fans weren't on, so maybe when the engine was turned off, the coolant heated a little more before cooling?

 

Whilst having the Pug, I've always tried to have the water temp half way or below when switching off, mainly for piece of mind.

 

See what happens tomorrow morning

[chocolate_o_brian 0]

Right... just did the following...

 

Got engine upto warm temp (3/6 bars, slightly over half way).

Flicked on fans while I popped bonnet up (as they're manual).

Turned heaters on full heat and power.

Took heat expansion tank cap off.

Topped up with water (as had to check from yesterday anyways).

Found bleed valve on hose near bulkhead and undid.

Let a little coolant dribble out while pinching the pipe in various places.

 

Findings...

 

With fans on, water temp remained steady at 3/6 bars on the gauge.

While bleed valve unscrewed, no bubbles from either valve or expansion tank.

Heaters seemed consistantly warm. Not hot, but a consistant warmness definitely.

 

 

So guys, on the above, does it sound healthy?

 

 

Having driven the car this A.M. I simply flicked the fans on everytime I came to a standstill, or very slow moving traffic. It seems the thermostats celcuis rating is approx. 3/6 bars on the temp gauge. Example being if I was driving at a steady 40mph and the gauge came to just over halfway, the temp would drop slightly. Then it would raise to about halfway again, regardless of fans being on or staying same speed. So I have assumed its the thermostat closing and opening around the equivalent halfway temp on the gauge. That does make sense in my mind lol

[GLPoomobile 958]

That sounds about right to me.

[chocolate_o_brian 0]

That sounds about right to me.

 

So just the big difference a thermostat makes then?

 

Think I'm gonna try get round to having automatic fans again, as it saves hassle to be honest.

[welshpug 1,657]

personally, I'd junk the manual switch and restore/replace the factory wiring and switch, you then don't have to worry about gauge watching and switching the fans on and off, you can concentrate on driving the thing!

[Tom Fenton 1,542]

As above, get the fan working automatically. I don't understand the fascination of people putting manual switches on cooling fans. Just make it work properly then forget about it!

[chocolate_o_brian 0]

As above, get the fan working automatically. I don't understand the fascination of people putting manual switches on cooling fans. Just make it work properly then forget about it!

 

Same here. I can't understand why the pillock that owned it before me did several things to be honest. These included...

 

1. Running the car with no thermostat

2. Re-using perished hoses with electricians tape

3. Recycling cracked hoses by cutting them in half and using copper pipe and jubilee clips

4. Installing a manual switch with wire so thin and uncapable of handling the current it melts the plastic fan switches every couple months

 

Seriously the guys a goon of the highest order. Luckily I have some sort of sense and have replaced what ever has needed replacing and done all the niggly jobs. If it comes to selling it eventually, the next owner will have a bloody decent car!

[mickie 3]

thermostats are great when they work but ive known people take them out, just because if they get stuck shut, the engine then over heats, normally warping the cylinder head, so needing a new headgasket and skim..

 

lot of work just because it broke down.. if i were you i'd take it out untill you got the fan to work on its own

[chocolate_o_brian 0]

Well driven the car a couple of days now. Warms up a treat and it seems the radiator is doing a sterling job of keeping the engine at the right temp alongside the stat and new coolant. Seems to stay at 3/6 bars there or there abouts all the time when warm, and I've noticed my oil temp seems to work too lol. Thought it was buggered - noop just never warm enough.

 

Gonna give it an oil change come Sunday when I swap bonnets too and stick my lovely Mobil 10w-40 in.

 

All I tend to do now after turning the engine off is run the fans for a few seconds for piece of mind.

[chocolate_o_brian 0]

***Double post***

Edited February 4, 2009 by chocolate_o_brian

[Alfie 6]

Well driven the car a couple of days now. Warms up a treat and it seems the radiator is doing a sterling job of keeping the engine at the right temp alongside the stat and new coolant. Seems to stay at 3/6 bars there or there abouts all the time when warm, and I've noticed my oil temp seems to work too lol. Thought it was buggered - noop just never warm enough.

 

Gonna give it an oil change come Sunday when I swap bonnets too and stick my lovely Mobil 10w-40 in.

 

All I tend to do now after turning the engine off is run the fans for a few seconds for piece of mind.

If sorting the wiring for the auto fan was causing problems, you could fit a sensor in the top rad hose as in kit cars. Its similar to Kenlowe fan system. you can adjust by virtue of a knob placed either under the bonnet or in-car. Ive used them with success in the past. Hope this helps.