I'm at the end of my rope with these coolant air locks over the past year I've drained and bled the cooling system more times than I can count every time all is well for a couple days then the temp spikes the heat disappears (yes the heater works very well) it got to a point where it over heated on the 401 head gasket went cooling system pressurized and all the coolant came out the expansion tank...so new cylinder head head gasket all the hoses t stat rad water pump etc eek:I replaced it all exempt the plastic expansion tank and cap
Today driving home from work temp all the way to the black, heat disappears lucky I was five minutes from home heat came back on just as I rolled into the village temp went to half I'm out of ideas need some help if it can't be resolved I will be parting the truck out I'm tired of spending more time under it than driving it.
The heat going away is indicative of not enough coolant in the system. This was happening to my Subaru STI recently and once I topped it up it went away. When I would stop at traffic lights the heat would go cold. Then the temp started spiking. Sounds very similar to what you describe.
You didn't give us much to go on, but think you need to:
Replace the thermostat
Remove the head and have it skimmed flat.
Have the top of the blocked checked and verified to be flat... if not flat you need to have the top of the block decked flat.
New head gasket
New P Gasket
What specs was the head torqued to?
My guess is when it is freezing cold the head gasket opens up and allows air in.
My guess on top of the above guess is this issue does not occur during the summer.
If above is incorrect, then you didn't bleed all the air our when the new head gasket was installed.
Have you ensured that the self bleeding lines are clear and the non return valves passing? The reservoir should get warm as the self bleeding coolant flows through it.
Sorry shouldn't post when frustrated with the Landy!!
Basically I've put a new head on and replaced the entire cooling system ( the old head warped I also had small coolant leaks P gasket 2 water pumps etc so I rebuilt the entire system ) I used the Haynes manual and followed it to the T spent three days putting it together making sure I got it right
I filled it up through the t stat housing slowly until the all the air came out of the rad plug ran it let it sit overnight still had air squeezed all the hoses until I was sure there was no air ran it let it sit overnight topped up the tank and all was well for two days then today I had the problem
The only thing I can think of I must be doing something wrong when bleeding it
Self bleeding? So if the heat goes temporarily and all is well again ??is it burping itself ??I just don't want to hurt the engine I understand from using the search I had major issues prior to the major repairs
After the first heat up you need to let it cool down and top it up. You can t let the level get low as the pump is very high.
The air bleeds out through the two small hoses that run from the thermostat housing and the rad to the reservoir. You need to make sure these lines are clear and coolant is flowing through them. They need to be hot when the engine is hot.
RDavis, Doug, Red and others know what they are talking about.
I will chime in and ask if you have done a pressure check on the system.
And offer that UK guys like to bleed cooling on an incline, to ensure rad bleed and bleed on T-stat are highest. May be voodoo, but Rovers like voodoo!
I have not done a p check on the new system all the hoses are new including the small hoses with plastic thingy last night I opened the rad cap a bunch of air came out then straight fluid buttoned it up and let it run without the cap on the expansion tank for 10 min put cap on took it out all was well but the gauge is constantly over half ..I just checked this at 1815 tonight so time to do it right unless you guys think I got it temp gauge was rock solid for hour and a half we will see still got 20 min to go all highway
Made it home 108 kph on the highway consistent heat and steady temp in 3/4 in the white zone with the lights and heater blower going and we all know how accurate the stock gauge is ��
The bleeder? Line that attaches to the timing case cover going to the tank was kinda squished on so I corrected that this morning before I left for work obviously I still need to go thorough the things mentioned above and get it p tested but right now the small lines are nice and toasty everything is good except the expansion tank hose that goes under the fan shroud to the T junction is only slightly warm?
Oh Red thanx if it wasn't for you none of my Landrovers would have worked!! Especially the BATUS ones!!
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Defender Source Forum
1M posts
24K members
Since 2003
A forum community dedicated to Land Rover Defender owners and enthusiasts. Come join the discussion about performance, overland, classifieds, modifications, troubleshooting, maintenance, and more!