Engine overheating

[Stagdad]

Well been at this all day, bloody cars!!!

Anyway put the car heater to hot, filled the radiator to max through filler plug/bolt, left plug off, checked level in the expansion tank, was low so topped that up, put the cap on and started her up. I got some air bubbles from the radiator plug, not much. Put the plug on and left her to cool down as she overheated.

Once cool took of the expansion cap and water down again, took off the radiator plug and topped radiator up, when I was filling noticed the level in the expansion tank went up. This time remembered to check all hoses, top hose very flexible but when I squeezed the bottom hose felt crusty inside, spent 10 minutes squeezing until it felt flexible like the top hose. Not sure what that was about. Started her up with the cap off and get a few more air bubbles out.

Let her go cold, topped up rad and halfway up expansion bottle, put the cap back on and started her up. Seemed to take longer to warm up, left her running and it did go over half way on temp gauge but not as hot as before. This time though the fan came on and the temp gauge dropped a little and fan cut off. That's a first normally the fan doesn't stop until 5 minutes after switching the car off. Appears to be better but still may be running a little hot. Didn't get to go for a drive will try tomorrow after checking levels. Fingers crossed.

Thanks for your comments again.

I would change that bottom hose, sounds like it's delaminating from what you have described.

[Scar]

I'd also suggest buying an infrared thermometer - look on ebay, they're usually yellow and cost about £12. Run it up to temperature and take some readings around the engine (cylinder head, radiator top hose, radiator body just below filler plug, thermostat housing and bottom hose). With the temp needle just past vertical in mine the top hose usually reads about 92, tad on the hot side but it's fine.

[StagJonno]

Glad things are looking up for you - you just need to get a decent drive (10 miles or so) to get a bit of confidence.

Good to see some photos - would have helped to see these earlier. I'd understood your reference to expansion tank to be in the original position. It looks like yours is closer to performing the function of a header tank, but I'm not totally sure as I can't work out the highest position of pipework relative to the tank. No matter, I'm more convinced that an airlock has been your problem.

If you have pipework (hoses) higher than the water level in your header tank, then I think you could be at risk of further airlocks developing here in the future and I would look to see if they could be rerouted to keep them lower.

I agree with Stagdad that you could usefully fit a new bottom hose.

Stick with it - it'll be worth it.

Jonno

[Carboy0]

Hi Bedfordstag, I am in Bedford too, if you want to compare cooling systems, chat, swear etc. happy to help, message me to meet up.

I agree with the others that from your pics the tank seems to be acting as a header tank and expansion tank. I run a Triumph V8 with the standard overflow tank, no viscous fan and a Revotec fan also fitted by Robsport. My fan will often stay on for 5 mins or so after switching off I have been cruising and it’s been V hot (like now) or if I have been “using the car’s performance”.

We can workout whether the tank is the highest point in the system relatively easily.

it sounds like you are getting there, as you understand more how your car works.

[BedfordStag]

Thanks to everyone who has contributed, I think a mixture of all the comments has sorted it, I am now the owner of a digital laser thermometer lol. Took her out tonight after checking the header tank level and for the first time, I didn't need to top up. Yay..... ran her up and the gauge was just over half. Checked top hose, 88 degrees, bottom hose 79 degrees, radiator by plug 87degrees. The fan kicked in at 86. so I am hoping all is well once more.

Thanks for everyone's help.

[garyf]

Hi Bedfordstag, I am in Bedford too, if you want to compare cooling systems, chat, swear etc. happy to help, message me to meet up.

I agree with the others that from your pics the tank seems to be acting as a header tank and expansion tank. I run a Triumph V8 with the standard overflow tank, no viscous fan and a Revotec fan also fitted by Robsport. My fan will often stay on for 5 mins or so after switching off I have been cruising and it’s been V hot (like now) or if I have been “using the car’s performance”.

We can workout whether the tank is the highest point in the system relatively easily.

it sounds like you are getting there, as you understand more how your car works.

I'm close in Newport Pagnell and happy to meet as well …...…...just a thought is your expansion bottle cap holding pressure ok??

[StagJonno]

Glad you're sorted. If anything, I think you could up the fan cut-in temp a tad. My understanding is that you need to be into the early 90's to get best performance/ mpg from an engine. Maybe others can be more definative about this. Mine comes on ~93C and off at ~88C.

Jonno

[Andy S]

Well been at this all day, bloody cars!!!

Anyway put the car heater to hot, filled the radiator to max through filler plug/bolt, left plug off, checked level in the expansion tank, was low so topped that up, put the cap on and started her up. I got some air bubbles from the radiator plug, not much. Put the plug on and left her to cool down as she overheated.

Once cool took of the expansion cap and water down again, took off the radiator plug and topped radiator up, when I was filling noticed the level in the expansion tank went up. This time remembered to check all hoses, top hose very flexible but when I squeezed the bottom hose felt crusty inside, spent 10 minutes squeezing until it felt flexible like the top hose. Not sure what that was about. Started her up with the cap off and get a few more air bubbles out.

Let her go cold, topped up rad and halfway up expansion bottle, put the cap back on and started her up. Seemed to take longer to warm up, left her running and it did go over half way on temp gauge but not as hot as before. This time though the fan came on and the temp gauge dropped a little and fan cut off. That's a first normally the fan doesn't stop until 5 minutes after switching the car off. Appears to be better but still may be running a little hot. Didn't get to go for a drive will try tomorrow after checking levels. Fingers crossed.

Thanks for your comments again.

Sounds like things are going well.

Mine took a couple of times to clear the air locks.

Andy S

[Scar]

Thanks to everyone who has contributed, I think a mixture of all the comments has sorted it, I am now the owner of a digital laser thermometer lol. Took her out tonight after checking the header tank level and for the first time, I didn't need to top up. Yay..... ran her up and the gauge was just over half. Checked top hose, 88 degrees, bottom hose 79 degrees, radiator by plug 87degrees. The fan kicked in at 86. so I am hoping all is well once more.

Thanks for everyone's help.

Sounds like you've got it running perfectly. Now go out and enjoy the Stag whilst the weather lasts! Agree with other posters that you might as well set the fan to come on at a higher temperature, no need for it to be on at 86, it'll be in constantly. 92 would probably be fine.