Ok my 99 Disco II with 114K mikes on it has been running fine, but I just looked under the hood while the engine was running just as a random check, and noticed bubbling in the coolant resovoir. I'm not getting any codes (no misfires, no apparent issues) but I understand that if I see bubbles, it may mean there is a cracked head or block,,,,should I be worried and looking for a new engine??????

 

Not so fast.

1. Could be bubbles from small coolant leak from a hose - missing any coolant? You can rent/borrow a pressure tester from auto parts store and pump up to 18 PSI and see if it will hold that for say 30 minutes, and look for any leaks. Drawing attached from RAVE of all the likely spots to check for leaks.

2. Could be combustion gas in coolant from leaky head gasket - any loss of coolant, white smoke from exhaust, overheating? This can run into money, if a head gasket. There is a chemical test you can buy from auto parts store for $35 - $50, does mulitiple tests (not just one time). It will confirm if coolant has bubbles of exhaust gas in it, which is a sure sign of HG problems. DIY HG is possible, $200 - 300 for parts, $200 for machine shop work to grind head back to flatness. $1550 - $1700 at indy shop.

3. Could be cavitaion produced by bad water pump. Check belt route to be sure we are going in the correct direction. A water pump is like $50 or a little more for the part and one hour of labor (well for me, maybe 2).

You need to be aware that HG and cracked block problems can cause rapid overheat. The heat gauge displays a lazy average from the engine computer, and it will make it 9:00 from say 135 to 240 degrees or so. If you want real time data, you can plug in a data reading scanner or an Ultra Gauge, which will show you the same digital info the ECM gets.

 

temperature stays right at a hair above half, no movement once it is heated up. I just recently had a temporary leak, were when I was driving, all of a sudden there was steam coming from the hood and, and something leaked coolant on top of the drivers side valve cover (towards the water pump side )- looked like about 5 or 6 tablesoons full, by the time I lifted the hood it wasn't leaking anymore......it's been a week and hasn't leaked again????????????

other than that no loos of coolant??????? and those bubbles, the more I look at it, may just be rough flow back into the resovoir....because when I llok down into the resovoir with it open and running, I don't see any bubles remaining on top of the fluid (unless the viscosity of the fluid prevents that.......hmmm

 

viscosity won't be a n issue, you had and event and there is a cause for it. Search now or pay more later.

 

check the hoses to your throttle body heater plate and the hose and pipes to and from your heater lines that come from the passenger side firewall. One connects, eventually, to the top passenger side of the intake, to the rear of the alternator, other than that, check out the larger hoses in and out of the block and the radiator. Like Buzz said, a pressure tester will help locate a leak. Better to find it now, in your driveway, than out on the road or on the trail. Good luck. Phil

 

The area you comment on is a simple heater for the throttle body, just and in/out small size hose loop. The purpose is to keep throttle body warm so fuel can't ice up at certain speeds, altitudes, and temperatures. If it ices up, throttle is jammed on just as you go over the mountain.

Kit to fix is cheap - see LAND ROVER PARTS - GASKET KIT TROTTLE BODY P38A & DISCOVERY II

These eventually go and a stream about 1/4 inch diameter spurts out.

 

Okay borrowed a compression testing kit, and you hit it spot on....the throttle body heater is leaking.....plus I found one other leak too......Ordered the replacement Kit, will be here Wednesday......so the guy at rovers north gave me an alternate idea till the part gets here - basically bypass the heater plate - it's still in the 70-45 degree range here so no fear of freeze up.......here is a couple picture to show you.....

 

Yes you can by-pass the throttle body heater until your parts arrive.