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Discussion Starter #1
Trying to work thru a few issues on my GF's 98 4.6...
Just did the valve block and pump rebuild, and now I have a concern about the temp gauge..
I did post a question about bleeding/burping the cooling system, and am thinking I got all the air out, but I still think the temp is too high.
On the freeway at 70ish mph it runs about 60% toward the Hot temp...
I ran it in my garage(with door open!) here yesterday with the ambient temp being near 90deg f and after about half an hour it had reached the end of the "normal" operating temp line on the gauge.
No Aux fans kicked in...
I did do a search and found some reference to them "never" coming on...
Can anyone enlighten me as to what is normal?
About the only thing I notioce that is unusual, is a tiny "blow" noise that I can hear from the RH exhaust manifold... I am gonna pull off the heatshield and see if I can see what it is.. I am hoping its not a headgasket... No oil in coolant or viceversa..
Ideas or experienced knowledge needed.. Thanks!
 

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Discussion Starter #2
So, I tipped the whole Range over with the RH side up maybe 6", and bled, and refilled the Radiator.
I ran the motor, burped and could nor feel any air in the top hose.
I refilled the expansion tank, and left it to cool. Topped it up when cold and put the cap on.
Today I drove it 8 miles, the first mile was 45mph, then 6 miles on freeway at 70ish... the temp stayed about midway on the gauge..
The last mile was residential, to my girlfriends house. By the time I stopped, it was almost into the red... :oops:

Anyone want to give me the bad news?
 

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Is it using fluid? Does the temp gauge change if you turn on headlights, rear demister, and crank the ac fans in the cab to full? Any leakage around the weep hole on the water pump?

I guess your in the United States.

How many miles on it? has it had any work done? could be anything, blocked radiator, air lock, all the way up-to the dreaded slipped liner. A bit more history would be great to try figure it out from afar :)

Personally spend the small amount of money and have the cooling system serviced by a radiator shop and see what they come back with.

There is heaps of info on the main site and the forum, but from my poor memory the AC fans only come on when the pressure switch is triggered by the AC line pressure in normal use, and or by a combination of temp sensors controlled by the BECM, but that scenario only kicks in when the situation is extreme. Could be wrong though.
 

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Discussion Starter #4
Info,
116k miles, Radiator replaced less than 2k miles ago, and I think the waterpump, fan, and viscous coupling were done maybe 5k ago.
I did searches for answers and diagnostics, and I think the top hose feels pretty hard, which concerns me. As mentioned above, when running, there is a slight "fluff" noise on the RH head, that I thought was a cracked manifold or header gasket, but could not pin it down.
Not noticed any coolant loss, but then I have been trying to burp the system. I will check it.
My first concern was that it was loosing coolant out of the overflow pipe, and the cap was not tight enough. On retightening, I think she had a low coolant condition, and thats when this started.
Its been sitting for the last month as we had a EAS fault that I just fixed.

I will drive it again tomorrow and get a IR thermometer reading on the Thermo housing to see what the reading is.
 

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I need to post my bleeding tutorial. The instructions in the rave manual suck. Basically you need to fill the block, radiator (by using the coolant pipe), and reservoir with 50/50 coolant. Let it sit overnight after running it, and then top up in the morning.
 

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Discussion Starter #6
Please post it....
I need to know if I am doing it wrong, or there is a problem.
Where is the best place to check the coolant temp with a IR thermometer?
 

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Discussion Starter #7
Bumped with the hope that someone will help me to diagnose if the system is just not burped, or if we have a headgasket failure...
 

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I bled my system by filling the block up first, then the radiator, then the reservoir. I then blew into the top radiator hose to get all the air out of the block. I then blew into the reservoir while plugging the relief tube. Blow into each several times, you will most likely hear coolant sloshing around and the air being moved. I started my rangie and the coolant immediately started going down. I turned it off and topped up, and then turned it back on. I gently massaged the hoses and let it hit its normal operating temperature. I shut it down and let it sit over night. The next morning the coolant had gone down some more, so I topped it up. I then started blowing in the reservoir and did not hear any bubbles. Fired her up and went for a drive. So far all is well... Almost forgot, make sure your bleed tube does not have coolant in it. Remove the tube from the radiator and remove the reservoir cap. Blow into the tube to clear the coolant out.

Your RR may not actually be overheating either. Mine has a short somewhere that causes the temp gauge to go more into the red with the more electricity I use. A scan gauge confirmed this. The normal operating temp range is 195 to 210F. Your fans should kick in at 210F and cool it back down to 199F, at least mine do...
 

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Discussion Starter #9
Ok, need a little clarification...
How does "blowing" into the block and rad get the air out?
I had the range sitting on my sloped drive,nose upward, and I let it settle on jack stands from high, to access setting, so that the Right side was sitting higher by maybe 6".
I cant feel any air in the top hose when its cold and I squeeze it.
If I leave the Res cap off and the engine gets to temp, it quickly overflows out of the expansion tank.
We are not driving it until I get this figured out... if its a headgasket, thats a pain, but not so bad.. freaked out about liners moving etc tho.
What started this was the Expansion cap not seated or sealed tight... I can twist it on as tight as I can by hand and can still hear a slight hiss, and it drips coolant from the overflow pipe.
i ordered a new one today.
I am gonna go and start it, run it up to temp and check a few spots for temp with my IR thermometer.
I have a Craftsman Cooling system Pressure tester, but not sure if it has an adapter for the Range yet.
 

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Hi,
it might be worth pulling the plugs out and seeing if they have any corrosion on them, if the second one back from the front have then your looking at a porus block, at least thats what mine was when i had the same, oh word of caution the plugs can get pretty tight, mine snapped off in the block!! mine never overheated when it had this problem but the top cap had begun to hiss, indicating that the system had overpressuirsed and blown the seal, it wasnt untill i replace the cap that the top hose became rock solid. mine was also dripping slightly from the overflow tube.
 

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Discussion Starter #11
Thanks for the info.
What if the headgasket is blown... I am leaning toward that...
I am a little worried by the odd noise I can hear on the rh side head.
Headgaskets dont scare me, did one 3 months ago on a Ford V6.
With 116k miles, what else am I possibly into?
Can someone explain the tophat issue or direct me?
 

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The top hat issue is most likely in reference to liner failure in the cylinders. Which, unfortunately renders the engine useless. A slipped liner usually occurs when the engine reaches a temp of 240F or greater for an extended period time. There are many posts on liner failures, do a search for them. Have you verified your temps? BTW I did not take the coolant cap off while the engine was running, of course it will cause it to boil over, its a pressurized system. I only blew into the system when it was cool. I could easy hear air bubbles moving in mine while blowing into the top radiator hose and into the reservoir. Whether you see a "point" in it or not, it worked for me, so I figured I would share. Head gaskets in these are not a huge problem. The Rover V8 is based off of a buick engine block and does not have over head cams, which makes it a bit easier putting things back together again.
 

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Discussion Starter #13
Thanks.
I'm a in fact a Brit living in California, and used to work at Pressed Steel Fisher in Cowley!
I remember the Rover V8 and know it a little having friends shoehorn a couple into cars like a Morris Minor...
The Ford I did recently was a Essex OHV V6, and they are notorious for headgasket failure and head corrosion, had to have a coolant passage TIG welded, then have them skimmed. In the middle of a Jeep 4.0 to 4.6 build with a stroker crank, roller rockers etc..
Point is I am a reasonably experienced mechanic, and the headgasket swap is not scary... I just want to be sure before I start.
Went over to the GF's to pull the plugs, and check the temps, but the plug wrench in my mobile set was too small, and the Battery was flat again(Its been sitting 2 weeks and clearly we have a drain somewhere). I didnt have my boost starter on me...
Hopefully I will do temps maybe today, and pull the plugs.

Talked to the PO to confirm some history.
The fan and Viscous coupling is in fact about 7 years old..., he had the fan let go... took out the rad, waterpump, and even the Hood! Then, just before we got it he had it serviced, and the radiator was found to be leaking, so that and hoses are about 3 months old and maybe 1500miles, so lets assume they are fine. This got me thinking about whats going one... Maybe the head gasket is leaking or the block is porous, causing the rad to leak, prompting its replacement, then the next weak link is the overflow res cap....

In reference to the statement about it overflowing, I left the cap off as per the Rave instructions, and was kinda caught out by how quickly it went from normal level in the overflow to gushing out over the neck as soon as the Thermostat opened..
 

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Discussion Starter #14
So, here is the update...
I started her up and let her idle for about 15mins... temp gauge was reading midway... after 20 mins it was creaping up and soon was on the top of the normal range almost into the red.
Top hose was hard, but not too hard that I couldnt make a dent with my thumb.
So, I took my IR thermometer and took readings, in Centigrade:
Top hose, engine end 98, and radiator end 94.
Radiator, top of plastic 94 to 90.
Small overflow pipe to tank by battery 102.
What happened next frightened me to death for about 2 seconds...
I was taking a reading on the heater hose that comes from the forward end of the intake manifold... and I swear I didnt touch it.. when suddenly they was a load HISSSSSSS the hose let go.... coolant began to blow out right where the clamp holds that hose to the fitting. In 10 seconds it was a steaming sweet smelling cloud.
I turned off the engine, put down some towels and walked away...
Just bad luck?
Or further proof that the HG is pressurizing the system?
 

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KeyRange said:
Thanks.
I'm a in fact a Brit living in California, and used to work at Pressed Steel Fisher in Cowley!
Join the club. I did my apprenticeship at PSF in the 70's, father still lives in Cowley :thumb:
 

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With regard to the "puffing" sound. I just repaired a 99 4.6 with just this symptom. Turned out to be the head gasket blown outwards toward the manifold on No 6 cylinder (3rd from left) Beats the hell out of me what caused it, head tested perfectly, block appeared ok no overheat and no slipped liner. Head bolts perhaps but who really knows. Anyway, there are no coolant passages in the vicinity of No 6 cylinder that I noted but you may have a problem on another pot that is leaking exhaust to the coolant. DO NOT continue to allow this engine to overheat. You are asking for trouble. If you feel it may be the manifold gasket leaking it is only a 1/2 hour repair and $10 for parts, if that doesn't do it, leave the outer heat shield off and run a piece of paper under the down tubes and under the head gasket. Any deflection will point to the offending cylinder / s.
Hope that helps, crude but effective.

Chris.
 

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Discussion Starter #17
Thanks for the input, I will look at the manifold... tried to get the heatsheild off and one of the bolt was seized, so I soaked it and will try again later.
Well, we are not driving it until I figure it out.
Is the 90 deg temp I read at the top hose be overheating?
Why would the overflow tube be hotter than the top hose or radiator top?
 

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Over presurising will prevent the water pump from pumping hence the high temps on top of radiator, pressure vs the water pump effect and it could be the coolant bottle cap at fault and a very common problem on P38s.

The pressure build as you describe is leaning towards blown head gasket as your one post describes how the hose burst, these motors dont always mix water with oil to have a blown head gasket and in the time I've done these motors I've never had one do so but only the little odd tale tell signs of higher than normal milky mix on the rocker covers baffle plates..

When or if you do the job make sure new head bolts are installed
 

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Discussion Starter #19
Now almost all moved in with my GF...
Still getting my tools and bench set up, but starting to think about the next move...
I will pull the plugs in the next few days, and was wondering what I can do to find out if I have a headgasket or slipped liner/ porous block?
I have a pretty good spread of tools, inc a compression tester and leakdown tester.
I am a little stuck on what to do at this point...
If I pull the heads off and find a headgasket gone, thats all well and good, but what if its a porous block or slipped liner?
Anyone care to give input on Irontite Block sealer as an option?
 

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I don't know what the Aux fan is actually for but it doesn't come on when the engine is hot!

It sounds to me like your RR has a slipped liner. You can test this by getting a fitting which screws into the spark plug hole and seals the cylinder. you then set your compressor up to hold this fitting to 100psi air pressure. Your cylinder needs to be able to hold that and more.

If you have a slipped liner, you will get bubbles in your coolant system. It can be pretty agressive, mine was. You need to repeat the test for each cylinder.

I never hear about head gaskets going in RRs. I'm sure they do but blocks seem to be MUCH more common.

The solution is
1. new block
2. rebuild with top hat liners (search for it)
3. scrap the car.

Of these options I went with 2. A good top hat liner job will last forever and you will never get slipped liners again. You also need to replace your coolant cap and any other suspect parts of your cooling system.

It took me months to make the decision to rebuild my engine - option #3 above was seriously considered. My RR is a really good one and ultimately I'm glad I did it. I've had it for 9 years already and will be keeping it a bit longer yet.

Greg
 
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