how strong are the 4.6 thor engines?

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funrover

funrover

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I've heard horror stories of cracked blocks, slipping liners, headgasket woes yada yada yada.

My 4.6 is quiet as a door mouse with 120k and as far as i can tell it has been well maintained.

how do i know if it has slipped liners or a cracked block?

according to the seller i bought it off she uses some coolant!. But there are no leaks she doesn't smoke and she idles beautiful.

are the v8s a ticking timebomb?
 
Last edited:
Liner normally ticks.

Losing coolant could be all sorts of things but just to be safe get some UV dye and drop it in the coolant. After a few days shine a UV torch (see eBay) on the dipstick and see if anything glows.

Head gaskets do tend to go around 120k miles.
 
The only version of the RV8 that is generally bomb-proof in this respect is the original 3.5. Once LR, in their infinite wisdom, enlarged the bore to 94mm the problems began though it has to be said that it's something of a lottery. I'm not an engineer but perhaps if the manuf. had simply increased the stroke (as they first did with the 4.2) & left the bore alone ...
 
If your liners slip, trust me, you'll know. Coolant cascades a foot into the air and your temperature gauge stays at 20 to instead of 12 o'clock. The offending pots plugs will be as clean as a whistle. You won't be able to drive any further than 20 miles without the temperature gauge flying over to max with a lovely red light on. You'll change the water pump, thermostat and radiator cap after bleeding the cooling system endlessly in desperation.you might even be truly cursed and got one that's had the magic gunjo cure that lasts 5 minutes, just enough to make the sale. Be prepared to get laughed out of town posting how your p38 can't melt butter.;) I know. I was that boy.
 
My first question is does this have lpg? How much does it loose? These are twenty years old now and could loose coolant from anywhere tbh and first of all I would pressure test the system cold to hot. Nothing obvious? Drop the oil check for coolant. Nothing? Change the plugs. Any cleaner than the rest? I would not commit further to this. Even if its a head gasket it's to much work for a casual driver if the block is cracked bail out. Run the car until it goes pop. Get another! Think very carefully before committing much money. (Unless your completely nuts... Like me!)
John
 
If the car is good otherwise and you KNOW that it has liner trouble, go to Turners for an exchange block, £1600 inc VAT, transfer your engine bits over.

Rest of the car is pretty much sorted after the 2000 MY.

Peter
 
You'll know if it's a slipped liner - start the engine from stone cold & let it warm up, a SL will manifest itself as a metallic 'tap' heard as the lump approaches/reaches running temperature. The noise will be at piston speed, not to be confused with possible valve gear wear which is at half engine speed & it will not necessarily use coolant - I ran my 3.9 for a couple of thousand miles before tiring of people asking if it was a diesel :mad:
 
The 4.6 is strong enough.. the only issue to remember with the 4.0 and 4.6 is head gasket failure.

If you are fairly competent you can do it for about 500 in parts including replacing other stuff you'll spot on the way.

Allow 2-3 weekends if you take your time.

Weekend 1 taking it apart with some swearing and making note of parts you will replace. And dealing with tge manifold stud on number 8 bottom and the heat Shields.

Weekend 2 start putting back together and finding out you've been sent incorrect items.

Weekend 3 putting it back together once you have correct items.

Follow rave.
 
Indy once told me a slipped liner presents just like a failed head gasket - my engine is a little "tappy" and uses a little coolant but the needle stays very firmly at 12 oclock and I have done two or three block tests over the years which have been negative.
 
Fergie46 said:
Indy once told me a slipped liner presents just like a failed head gasket - my engine is a little "tappy" and uses a little coolant but the needle stays very firmly at 12 oclock and I have done two or three block tests over the years which have been negative.
Click to expand...

For about £20 you can get an electronic stethoscope which is very good at tracking down where the noise is coming from. For a fiver you can have a bog standard one.
 
Much is down to care, our 4.0 Discovery 2 was bought in 2009 with a very poorly 4.6 engine in it, very poorly fitted as well!

We found a new crated short engine, £800 with carriage, then found it was a GEMS version not a THOR, but the only difference was the crankshaft/flywheel pickup, which we modified.

That has done nearly 100k miles now, head gaskets leaked at the water joints at 45k miles, which we put down to crap gaskets from ebay. Bought a Reinz gasket set and it has been fine since. Elring has been mentioned as a good product as well. One set of gaskets we bought had no 'TOP' marking on the gasket faces!

Coolant is the key: both the type and the level. Ours runs on 50/50 OAT and we run it with the level 1/2" above the seam on the header tank. We lose a bit from various areas, but on a trip to Europe this year water consumption was almost nil. It loses more in the winter.

We check it before any significant trip and keep OAT in the back for topping up.

So many of these engines suffer serious internal corrosion through lack of anti-corrosion additive.

Hopefully the Rangie we are working on tight now will turn out OK, but if not we are going to get a Turner engineering block for it and swap the parts over. £1600 plus gaskets etc.

Peter
 
Seriously think very carefully about stripping anything. Cracked block is the classic issue usually on the back 2 cylinders after overheating. Symptoms? Initially minor coolant loss the same as every other v8 issue! These run hot when there fine. Live with it for a while poke at it and fiddle. £1600 for a short motor plus £500 for hg plus x plus y. Plus 50 hours graft etc etc. Huge commitment on a £600 vehicle. Limit your spend in other words don't become trapped!
Jb
 
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