4.6 Engine overheating

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paulblake427 said:
What was the cost of the short engine ? I guess there are no other routes to get orignial block repaired ?
Could you comment todays repy (mine) please.
Click to expand...

Before you lash out on a short engine, find out why you have no water flow. A not uncommon problem is the water pump impeller turning on the pump shaft so it fails to pump adequately:)
 
Many thanks but all is good on that front, I am going to take the pump off and try and check the water flow in the block, I have previously used a "seal head gasket/cracked blocks" solution but it appears not to have bunged things up. Further investigations carrying on.
 
Many thanks for input; checked water flow rate with hose pipe through pipe that goes to heater in matrix, water flowed through block and out of each side of pump (each bank) fixing (pump was off of engine), put hose pipe through top hose connection to engine same result all good with no sludge or anything of concern. Latest test; Carried out same test as before but with top hose "T" (smaller pipe to Thermo disconnected), all filled with water so that cooling system was all inplace. Water could be see at top of the T pipe. Started the engine:- tickover 20 seconds (cold) no water movement, reved to 3K so a little movement then some then none. I have discovered that the w/pump is a non OEM part (From Eurocarparts), I will now be looking at OEM part to see if any difference.
 
paulblake427 said:
Many thanks for input; checked water flow rate with hose pipe through pipe that goes to heater in matrix, water flowed through block and out of each side of pump (each bank) fixing (pump was off of engine), put hose pipe through top hose connection to engine same result all good with no sludge or anything of concern. Latest test; Carried out same test as before but with top hose "T" (smaller pipe to Thermo disconnected), all filled with water so that cooling system was all inplace. Water could be see at top of the T pipe. Started the engine:- tickover 20 seconds (cold) no water movement, reved to 3K so a little movement then some then none. I have discovered that the w/pump is a non OEM part (From Eurocarparts), I will now be looking at OEM part to see if any difference.
Click to expand...


I still reckon you pump is fecked, the impeller is slipping on the drive shaft under load.
 
Guys, really not the pumping meaning the impeler is sound. Will pick OEM unit tomorrow to compare non oem and OEM (£251.00 !!!!!). will report tomorrow.
 
HI all, my RR 4L V8 over heated about 5 weeks ago so i changed the thermostate and it has been perfect but today it done the same thing the temp gauge jumped over to the right and the light come on.

any iders im going to change the water pump next.
Do you think my head is cracked as it has been driving perfectley for 5 weeks?

Regards Mark
 
Delta351 said:
HI all, my RR 4L V8 over heated about 5 weeks ago so i changed the thermostate and it has been perfect but today it done the same thing the temp gauge jumped over to the right and the light come on.

any iders im going to change the water pump next.
Do you think my head is cracked as it has been driving perfectley for 5 weeks?

Regards Mark
Click to expand...

What make was your thermostat and did you buy it new? When was the rad last replaced? You really need a complete overhaul of the cooling system, esp in these temps. Blocked Rad, duff thermostats, broken pumps, stuffed fans, wrong antifreeze mix will not help. V8 esp needs it to be in tip top condition.

Today was the hottest day of the year and at temps above 30 these trucks will struggle with "already marginal cooling systems" (datatek 2012 :)). Ther'es a reason you never see a P38 on African overland trips!

My diesel was trying to push itself into the 1 o clock position today but I had heating on full wack and reduced the fuel input (plenty of coasting and avoiding hills!) to a minimum to keep it in 11/12 o clock position. I saw a D3 towing a horsebox today taking it very easy as he pulled off from a junction...we could have almost had a conversation as I passed him :)

Head unlikely if it was fine for 5 weeks (depends if you have a heavy foot) however your overheating issues will not help the situation and will eventually lead to head failure if it hasnt already. IMO these cant be driven hard or even normally on days like today and I always make sure I have the AA card close by on hot days.
 
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Hi there. ive only had my rr for 8 weeks its almost mint condition 72500 miles full service history.
thermostate was an ebay buy, ive just ordered a water pump & rad from www.p38spares.co.uk
the water mix was perfect so im hoping its the rad or pump!
is there a mod to replace the viscous fan with a permanent electric one? for better cooling?
 
Delta351 said:
Hi there. ive only had my rr for 8 weeks its almost mint condition 72500 miles full service history.
thermostate was an ebay buy, ive just ordered a water pump & rad from www.p38spares.co.uk
the water mix was perfect so im hoping its the rad or pump!
is there a mod to replace the viscous fan with a permanent electric one? for better cooling?
Click to expand...

If you've got aircon then DATATEK on here will supply you with details of how to use those fans for engine cooling.
 
possibly Kenlowe but not sure...Others may be able to tell you. Best cooling is removing the bonnet all together or cut a 'Jeremy Clarkson viewing hole' in it!

viscous fan should work ok providing its actually working...do the newspaper/hand test.

72500 is a good mileage for overhaul, depending on how the previous owners treated it.

I might suggest you need a new thermostat if it was obtained from that famous online auction site! Get OEM or similiar from Rimmer bros or Island 4x4 (not affiliated).

If you're really passionate about it, get a diagnostics run, to see if any of your cylinders are running lean. This will certainly push the V8 over the edge on hot days.
 
Last edited:
Delta351 said:
Hi there. ive only had my rr for 8 weeks its almost mint condition 72500 miles full service history.
thermostate was an ebay buy, ive just ordered a water pump & rad from www.p38spares.co.uk
the water mix was perfect so im hoping its the rad or pump!
is there a mod to replace the viscous fan with a permanent electric one? for better cooling?
Click to expand...

If you change the pump & RAD, change the stat at the same time but check that the new one works before fitting. Viscous fan is often the cause of overheats. I can give you a mod to use the aircon fans as suplimentary cooling. Forget Kenlowe, they appear to be very unreliable these days.
 
Many thanks for all suggestions. Latest is oem w pump fitted and still cannot get any real constant water flow, cold or hot. This is getting interesting, engine full of water with top hose lifted off of metal up pipe. On starting there is mostly NO water flow out of it at any rpm when cold or hot. If anybody out there really investigated cracked block syndrome does or can it cause gases to go to the water pump and cause to not move water ? Please help.
 
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