overheat issue
 

Hey all, i have a overheat issue that sprang up today at hwy speed.It the RR and not my daughters disco II...thank god or she'd kill me....

history: headgasget done 40,000 miles ago,
expansion tank replaced last week
checked thermostat in boiling water to test opening
top hose always a litttle tight but can still squeeze
no milky or condensation in oil spout
starts and runs great not even a misfire...even today when had problem
just did 60,000 mile service a week ago myself
flushed cooling system and added new coolent a month ago
replaced waterpump 3 weeks ago as berring was going...had a play as i heard it when looking in bonnet
my cooling fans running always...rewired as i live in miami....hot

today at hwy speed i noticed a spike and the needle going to the red. I pulled over and opened hood. My top hose was hot, bottom comming out of raditor was warm...wel not as hot. i had bubbles expansion tank. I slowly opened and let steam out. waited a bit till cooled down and restarted. I left expansion tank cap off to see what is going on. I start to notice small bubbles running up to the expansion tank as it gets at operating tempature. I shut off and waited to cool as i was only a mile from home.Restarted and craweled home at slow speed with expansion cap loose enough to release pressure. yes i did top off before. I got home and was 1 oclock on the temp. Opened hood and the tank was releasing pressure.

Waited to cool down a hour and then refilled tank to correct level and restarted and did a block test when it got to normal temp...12 oclock... a few tinny bubbles and stuffed the block tester on the expansion tank. Fluid stayed yellow and did not go to blue. I have no smoke in the tail pipe and is not wet. Purs like a kitten even when going hot....

could this be that my head gasget has a tiny leak? i have no collent loss. The only thing i could think of is that maybe that my top hose was a little tighter than normal maybe it was slowly going?

the time i had my headgasget done it was boiling to the expansion tank not tint bubbles like now.....did i catch it early? i hope a headgasget job should last more than 40,000 miles....

Anyone to chime in would be great...

Thanks all.....Chris

Being that you just worked on the cooling system, my best guess would be that you have an air lock. There is a simple procedure in the rave manual to correct it. Mine was a real pain to get all of the air bubbles out of it.

airlock
 

i was thinking the same but i did the bleed as the rave states and have been driving for 2 weeks fine. I have a sneaking suspicion that for some reason my harding of my top hose is linked to a slowly developing headgasget leak. i think i caught it early. The time i did have to do my headgasget it was bubbeling like crazy when you got it up to operating pressure. Now its just a small fish tank kind of bubble that starts as it gets to operating presure and does not go faster when accelerate the gas which leads me to belleave its tiny.

How about a year and model, would help?

hey mike
 

year is 1995 range rover 4.0 se...

First, never open the system on an alloy engine when she is hot, you can warp the heads.
Always let the engine cool down, if not leaking coolant, by turning your heater full hot, keep the hood closed and let it idle till back down to operating temp.
Are you sure you are bleeding all the air from the coolant system?
If you are then I would suspect another bad head gasket, might want to have a coolant pressure test done, then either a chemical block test or test the coolant bottle with an emission sniffer to see if you have exhaust in the coolant.
Let us know what you find and don't drive it much if any till you get it repaired.

overheat
 

well, i started it up today and let it get to operating tempeture. I had to shut off as i didnt get any bubbles but i did get pressure as i had the cap off and it was getting to the filler neck. I started after about 5 minutes and then i could get the small bubble. Leak test negative again. exaust...normal ...no white smoke. I started to take off one spark plug wire at a time to see if i could locate the cylinder. still bubbles. well bubbles with no exaust to turn test blue, i am thinking a pin hole in the head gasket or the thermostat. i am going to take out the thermostat and break threw the actual valve inside so i can get a constant flow and see if that is causing it to maybe boil over. It's 95 degrees here as of 10:00 this morning so i figure its at least 250 degrees in my engine compartment as i have a black truck so it should always be open. I will post what the results are in a hour or two once the truck cools down.

Hey mike, my heater matrix is bypassed. I live in ft lauderdale florida and it's always fricken hot...its 95 degrees at 10:00 this morning so i figure its about 250 degrees in my black trucks engine compartment. i remember when i was living in the islands the locals use to take there thermostats out and then they would drain there fan clutch and drill them and bolt them so they where always blowing hard. they kept ther cars for years with no heating issues...:cool:

update
 

Well , i knocked out the thermostat on the inside so i can get constant flow. It took a little longer to come up to tempeture but when it came to 12 oclock, it stayed there. i also have the bleeder hose disconnected or off to bleed. Well, i only get a little steam and i ideled it for 30 minutes. pured like a kitten. When i connectd the bleeder line, after about 10 minutes it started to go hot. i turned off and let coool for a bit. disconnected bleeder hose and steam comes out. restart without bleeder hose connected and will idel forever. I am guessing a small pin hole leak somewhere or i did replace the water pump a couple of weeks ago...would that cause air or pressure to get in the system? i checked it today and it will turn and has no play as i took the belt off and checked. does anyone know how much it should spin by hand? it feels like it has resistance but it will turn by hand easy. ANY THOUGHTS? http://rangerovers.net/forum/images/smilies/think.gif

Thanks Chris

The hose you have disconnected, becomes clogged sometimes. Blow it out with some low pressure compressed air. If it is working properly, it should have a constant stream of water that flows into the overflow tank.