How to flush out heater matrix on p38 ?

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
W

Willos

Active Member
Posts
521
Location
Huntingdon Cambs
Drat it happened again:mad:. Just when I thought I was over this overheating lark it happened again on the way home last night.
temp gauge right over with red light on. Shut down on the spot. waited a few moments and lifted the bonnet. Just caught in time before mega steam. The pipe from the top of engine going to the heater matrix was red hot and the return substantially cooler so I can conclude this is blocked and causing restricted flow. It had just done a 250 mile round trip to pick up a trailer tent so I was luckey I was only a mile from home.
Started her up a few minutes later and the temp gauge was in the centre went a few miles and back in the red again. Same very hot /cool with the inlet outlet pipes on the heater matrix.
Whats the best way to flush this out . Anything I have to have on re controls inside to get max flush of the matrix.
 
I found some coolant "detergent" in the garage the other day (Halfords 2 part cooling system cleaner). I plan on sticking it in mine and running it for a day or two too loosen any sediment, then thoroughly backflushing the rad, block and heater matrix to really shift as much muck as possible.

Knowing my luck I'll find out the hard way that my block had gone and the detergent will clear out the bodgetastic K-seal or Radweld the last owner probably poured in to mask the problem...

Malcolm
 
malcolm_durant said:
I found some coolant "detergent" in the garage the other day (Halfords 2 part cooling system cleaner). I plan on sticking it in mine and running it for a day or two too loosen any sediment, then thoroughly backflushing the rad, block and heater matrix to really shift as much muck as possible.

Knowing my luck I'll find out the hard way that my block had gone and the detergent will clear out the bodgetastic K-seal or Radweld the last owner probably poured in to mask the problem...

Malcolm
Click to expand...

Then I would suggest you just take the rad off & flush it seperatly then.. there was a post on here a few months back on the easiest way to tell if the flushed rad was clean

Take it out, empty it & WEIGHT IT.... then flush it & empty it....Then WEIGHT it AGAIN Somebody (can't remember who ) got bout 4Kgs of ****e out of theirs

i.e. when taken out it weighted in at 14 Kgs after flushing it weighted in at only 10Kgs.......
 
Ta for the advise. Does the return from the heater matrix go into the thermostat ?
If so blockage might be around here. Instead of flushing a 10 year old rad out I think a new ones in order and a good flush of all the rest. As stated it will clear all the muck around a corroded passage and end up with the same cooking recipe.
 
Blocked rad's is a common fault on P38's and the source of many overheating problems. A few years ago after fitting a new engine, still had erratic overheating. Replaced thermostat etc. without any joy and decided to ignore the radiator as it had flushed out clean without signs of muck when the old engine was removed. Finally bit the bullet and bought a new one.....guess what??....overheating disappeared, temperature gauge never moves from centre position and it's been like that for a good few years now.
 
Willos said:
Ta for the advise. Does the return from the heater matrix go into the thermostat ?
If so blockage might be around here. Instead of flushing a 10 year old rad out I think a new ones in order and a good flush of all the rest. As stated it will clear all the muck around a corroded passage and end up with the same cooking recipe.
Click to expand...

Willos,

if you buy a new rad make sure you get one with the BAFFLE in it .. there are some out there without it .. do the "Marble" test

When you get the new Rad .. drop a marble into the connection & see if it rolls out the other one if it DOES it aint got a BAFFLE & its next to useless... if it dosen't then it HAS A BAFFLE ( Jiggle the rad about until the marble drops out of the hole you dropped it into ...)


Keith
 
why is it useless without the baffle. I cannot see my local rad dealer saying no problem to that. Mines a thor engine with the pipes at both ends . Does this come with a baffle ?
 
Just took off the old one. Lot more to do than what rave says, like take off fan and undo bolts at the bottom corners of the rad.
Flushed it out and no crud but a lot heavier than I would have thought an ally rad would be. The thermostat had rubber sealing rings inside coming away.
so fetched new rad from Kempston rads(£138) and ordered a new thermostat from Rogers of Bedford(£19). New rad was a lot lighter and kempston said that the rads rhat come in never leak but are blocked, so heres fingers crossed its the rad and thermostat thats at fault here.
 
You must log in or register to reply here.

Similar threads

G
Series three heater matrix blowing cold
Replies
11
Views
620
Citizen Kane
C
Lej
Diesel heater + existing ducts
Replies
0
Views
274
Lej
Lej
B
Mistake with coolant flush?
Replies
11
Views
936
Bellhouse
B
JT_spark
P38 DSE Auto intermittent lack of power after vehicle has been hot
Replies
8
Views
625
brianp38dse
brianp38dse
P38 Monkey
P38 heater o-rings: draining tips?
2
Replies
27
Views
768
P38 Monkey
P38 Monkey
Back
Top