Over heating or is it?

[Doulou]

Two posts in as many days, sure thing summers coming!!!

Took the car for a drive last night and a strange thing happened. Water temp gauge went right over to the red after being at traffic lights for 3 or 4 minutes, engine was allready warm as I had been driving for around 20 minutes. As the lights changed and more air was able to flow the temp went down but only slightly. There were no signs of any over heating at all though!!

My questions are

1 - how easy is it to clean out the rad fins to get more air flow?(Without removing the rad) Is it just a case of pressure washing???

2 - would running a freescan help me check the water temp? (Never used freescan before) so forgive my ignorance.

3- could it be faulty gauge or thermostat, and how would I check them?

Thanks

Paul

[Jonathan]

1. Reasonably hard becuase of the fan cowling. Pressure wash would higly likley damage the radiator and the chargecooler rad infront of it....you've been warned ! Ideally lift the car up, take the fan cowling off and clean it that way using an air line or similar.....blowing the dirt BACK the way it came, not vice versa

2. Yes.

3. Yes. See question 2. Freescan uses the engine ECU temp sender (located under the inlet manifold) Dashboard uses a sender located in the water pump - they invariably tell different stories but the one to trust is the freecan one. I had to put a trimmer / calibration onto my 1997 car so that it reads the correct temperature.

Quick tip - gauges are a (very) rough guide, Freescan is god becuase it is the ECU telling you what is going on and the ECU controls the engine so it matters.......a lot....

Edited April 21, 2011 by Jonathan

[Rich H]

Having had the rad out I'd recommend taking it out to clean it. It will take ages to start with as the bolts with be rusted solid.

My radiator looks mint from the back.

The front looked like it was deliberately filled with compost! it was rotten too and needed re-coring.

[rogerch]

From your description, I'd check your fans are coming on. When mine come on in traffic I see a marked drop in temperature, before I get back out on the open road.

[CHANGES]

Sound like fans not coming on to me too.. The wires, conectors and relays are only just good enougth for the job, I had all sorts of issues with mine, constantly playing up....in the end made new loom and fitted with relay to each fan with new conectors ect,,,, problem solved.........NB the overall control has to stay with the original relay wiring though...

Dave

[Doulou]

thanks guys - fans are working for sure, that's why i'm wondering if the air flow is restricted due to blocked fins

Hi Chaps

just ran a freescan and sure enough it looks like a faulty gauge. Fans cut in at 92.8 degrees and drew the temp right down to 86.8degrees. However when the fans cut in the temp gauge shot right over to the red, as the fans cut out it returned to showing around 95degrees. Must be some kind of electrical fault somewhere. But really good news that she's not over heating.

Paul

[CHANGES]

Good news on the fault find ... and bad news on the fault find, if you get my drift.... sound like an earth problem , which was the side my problems with the fans came from ,,,

[rowge]

Drove to work today temp gauge usually goes to approx 98 degrees then drops back to 94 degrees after fans cut in, warm day today,also found a tiny leak from small hose that joins water pump to solid curved pipe, anyway today 100 degrees but not into the red I think fans cut in but then on motorway stayed. At 99 degrees I was expecting it to drop,then turned heater to hot and fan on and the temperature instantly dropped to 95degrees got to work 98 degrees, checked levels all ok, could the leak have created an air lock, don't have freescan, what else can I do as a quick check as I am hoping its the gauge/sensor

[philip600]

Freescan or Espritmon would be helpful as there are two temperature sensors, one for the gauge & one for the ECU. You can then tell if it's the gauge reading that's incorrect or the engine is running too hot although if the fans are coming on it would suggest it is getting too hot. My fans come on when the gauge is showing just over 90 degrees & Freescan shows my gauge & ECU sensor are about the same temperature & most of the time when driving my gauge never goes above 85 even with spirited driving, the only time my fans come on are while sat in traffic or if I leave the engine ticking over after a run.

A small leak shouldn't have caused an air lock, more likely your thermostat is faulty or the radiator may be partially blocked either inside or from debris coming in through the grill, this seems a common cause on the Esprit.

Phil.

[rowge]

Drove home, heater on hot and fan going keeps temp at about 95 but turn to cold and temp goes up to 99 maybe more dont want to chance it, refurbished the radiators a few months ago, so seems like thrermostat especially as when heater is on the car cools down a bit, any tips as I do not want to snap the bolts off, will spray with plus gas etc, fingers crossed, also don't want coolant all over my cambelt what's the easiest way to partially drain system just enough to change the thermostat

[Vanya]

As others have pointed out - this is most likely an earthing problem. My car sees certain gauges drifting when accessories are activated. For instance, when I turn on AC which triggers the compressor and the fans, the temp gauge goes up to the beginning of the red marked area. Likewise when I turn on my daytime running lights, the same gauge drifts upwards (note the gauge settles at these points until the accessories in question are turned off). Last but not least, when the silent alarm is triggered (in which case my indicators flash) the gauge rocks in time with the indicators. Funny electronics on these cars sometimes.

 

Sounds like running an extra earth might be a good idea.

[rowge]

Just removed the thermostat, it has 2 off holes drilled in it, both are 6mm diameter, put the stat in boiling water, no movement so the water has been passing through the 2 holes, just as we'll or I guess I would have overheated

[ramjet]

I just don't get that.

Someone previously has obviously taken the thermostat out and tested it. Didn't work so drill holes in it to allow water through. Why wouldn't they just buy a new one?

 

I was going to suggest thermostat, but everyone jumped in with fans. Glad to see you found the solution possibly and hopefully that is all it is.

[sailorbob]

Thermostats often have a hole fitted to allow the the air pass through when filling the system. Maybe this particular one had two as standard.

[rowge]

Had a good look at thermostat it is made in England wax stat it has the words flow and an arrow adjacent to one of the holes, this hole has been opened up and another hole added, agree makes no sense apart from maybe a safety device if the stat fails?

[ramjet]

Quite familiar with one hole in a thermostat Derek. Every thermostat I have ever changed has had one. I've not seen a two hole example.

At any rate, if it is not opening when tested, it's shot.

[rowge]

Got a new stat, it has 1 hole in it with a brass rivet flattened on one end, so it moves in the hole, I have removed this as it might work loose one day, hole is approx 1/16 inch, anyway placed the new one in boiling water, as I have previously bought stats that did not open even when new, this one opened up lovely, tested the one with the 2 off 6mm holes in boiling water, it eventually opened slightly but nowhere near as far as the new one, anyway installed new stat, jacked rear of car up, filled with coolant, ran car topping up as necessary, replaced cap and watched the temp gauge rise to 82 degrees, it stayed there for a while, the started to rise again, by this time inlet and outlet on radiator were hot, when temp reached 95 degrees fans cut in and reduced temp to 90 degrees, so happy days, not driven car yet, be interesting to see what temp is achieved on motorway