Hi, brand new to this forum but I have a ‘04 discovery II with Bosch 4.6. that has one or two blown heads. I wanted to know how I can determine if both are in need of replacing, short of removing the head itself, and also if you guys on here think that it would expedite things for me if I were to buy a set of rebuilt heads ready to go just needing to be installed, rather than take the time to find a machine shop to machine mine if need be & all the other things that needed to be done to them prior to putting the old original heads back in. My thoughts are it would be much quicker & more convenient to buy a pair. I’ve found a set online for $175. Also, how can I tell if machining is necessary on my heads. And the last thing is, the reason mine got in this shape was the alternate fan fuse blew & caused my motor to overheat one day & after researching online I found out about the fan & replaced fuse & all seemed well again. But the following Monday on my way to work, & every thing was seemingly fine so I t thought id fixed it til I crossed a long bridge & came to a red light & saw steam from under the hood & knocking & sputtering etc but my temp guage was right in the middle where it always was when it was running as it should but yet the motor was boiling over!? How is that possible that my guage worked 2-3 days prior to that day & let me know it was overheating, I fix the fan & all seems back to normal only to have it overheat way too much causing me to blow the gasket(s) yet guage reads as normal temp. And how would I fix that & keep it from ever happening again? Any & all helpful & productive advice is very very much sincerely appreciated, so thank you in advance for it.

 

The temperature gauge on the Discovery is notoriously bad. They are virtually useless and most often they don't show an overheat situation unless its too late. Do yourself a favor and get an Ultra Gauge. It will show the accurate temperate at all times..along with various gauge options and trouble code alerts.

 

If u are going to do one Head, do them both.

Get a Scangauge/Ultragauge to monitor temps. The cars temp gauge is useless.

I wrote a blog on my HG job last year, was my first time doing it. Just look for my threads.

You’ll get lots of useful and often conflicting advice.

For the heads, ABran sells refurbished that will save you time and headache, and won’t cost much more than having a shop clean and check yours. Have the valve stem seals changed if u don’t.

I would highly recommend getting ARP Studs, or genuine stretch bolts, and a gasket set from Fel-Pro or a manufacturer better than Britpart. Use genuine hoses and pipes. Britpart parts caused me fits.

 

That’s really good to know. I appreciate the info. This is my first Land Rover & I like it a lot, wish I’d known that a couple years ago. Hindsight being 50/50 & all. This happened nearly two years ago & it’s been sitting in my driveway every since but I’m ready to get it back going again. Thanks

 

f u are going to do one Head, do them both.

Get a Scangauge/Ultragauge to monitor temps. The cars temp gauge is useless.

I wrote a blog on my HG job last year, was my first time doing it. Just look for my threads.

You’ll get lots of useful and often conflicting advice.

For the heads, ABran sells refurbished that will save you time and headache, and won’t cost much more than having a shop clean and check yours. Have the valve stem seals changed if u don’t.

I would highly recommend getting ARP Studs, or genuine stretch bolts, and a gasket set from Fel-Pro or a manufacturer better than Britpart. Use genuine hoses and pipes. Britpart parts caused me fits.
Ok, thanks man. I really appreciate that. I was planning on buying just whatever came with the gaskets off, of ebay. I’ve came across a few threads on here that mentioned the head bolts being important tho, as to which kind you put back in the head. And I thought the same thing on buying some refurbished heads. It just makes sense to me that it would be faster & a lot less of a hassle. I’m mechanically inclined well enough to do really anything just about, if I had to but if I’m being honest, I don’t enjoy anything about it really, other than saving myself money. It’s ridiculous what most mechanics will try to charge you for any engine repair past anything that’s just not obviously simple.
I really appreciate your input. Thank you.

 

Good parts/gaskets will save you time, hassle and money. Get a kit that has molded valve/rocker cover gaskets they are much easier to install.

The RAVE Manual has all the instruction u need and threads like mine can help with tools etc.

Get baggies, labels and keep a log of steps. Being organized helps immeasurably.