4.6 Temp issue

Over the last week I have noticed that the temp guage takes longer to get to the halfway point where normally it would sit happily all day but now goes from halfway, down to a quarter and eventually back to half and then down to a quarter and so on. Also, when in traffic or at lights, the air flow goes from hot to cold. I suspected a possible air lock but as no fluid had been changed couldnt understand why. On the weekend I checked the coolant level and found the reservoir empty, topped this up and left the cap off to expel any air in the system, after a while there was return flow coming from the pipe back in to the reservoir but the the coolant started to rise and would have come over the top had I not put the lid back on. I checked the usual places for mayo, none found, and looking at the coolant, I cant see any oil mixed in. Now I'm not sure if this is pressure being forced in to the cooling system from a blown head gasket or not. Everything else is running fine, no misfires, no problems starting up either hot or cold, even if I leave it for 2 or three days. No LPG installed so no issues on that side, and I can squash the radiator top hose when it's at normal operating tempreture, although how hard this should be to squash is hard to measure. Anyone had anything similar and could offer some pointers, if it doesnt rain the weekend I will take the spark plugs out and look for any that may be steam cleaned.

You have to remove that small hose from the rad and blow it through to expell any water before you top up the system. If you dont the air will not bleed from the system. Have another go. You may have slight water loss from any of the connections, check them all when the engine is hot. Check the carpet in the drivers footwell, maybee your heater matrix o rings gone.

Hi Rewmer, will give that a try for sure, O rings were changed last year and carpet is dry so thats one good thing, will let you know how I get on

Do you know if you have a Thor or Gems engine ? The later Thor ones from 99 on have a heated throttle body. They have two small pipes under which are prone to leaking.

It's a GEMS unit. I noticed that the reservoir was at the correct level when I took the cap off but when I started it, this emptied out, topped it up and disconnected the pipe coming out of the top of the radiator, there was air coming out in between the flow of water. I blew the pipe clear before reconnecting and ran the engine around the 2,000 RPM mark for 1 minute then checked again. No flow coming in to the resevoir so disconnected the pipe again and revved the engine from under the bonnet, more air, so I topped up the resevoir and kept this going. Good heat inside the car, no more air seemed to appear and the water was not trying to blow over the resevoir but I didnt see a return flow. Ran this morning and it took a long time to reach half way but seemed to stay there. Suspect maybe thermostat is faulty. Will be using the RR all this week so will see what happens and report back

rewmer said:

Do you know if you have a Thor or Gems engine ? The later Thor ones from 99 on have a heated throttle body. They have two small pipes under which are prone to leaking.

Click to expand...

both engines have this system, it was the cause to my liners slipping.

i would suggest the op gets a sniff test done just to help clarify the issue.

a thorough check around joints for any evidence of leakage and even back flushing the rad and heater matrix.

then new stat, just to eliminate or at least the current one checked in a pan of just off the boil water.

then its going towards liners/HG:doh::doh:

wonder if the pump could be on its way out???

also check fan vissy coupling???

A sniff test is probably the way forward, the temp guage was dropping agin this morning on my way in to work. The fan and pump have both been replaced within the last 12 months so I have ruled them out, the stat may be an issue but I would have thought, once up to temp, it wouldnt drop again. Liners/HG obviously not want I want but I will let you know what the sniff test uncovers.