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    • #57257

      I have an original style Tiger radiator of unknown history. A few months back, when the radiator was removed during my engine rebuild, I back flushed it and removed a lot of brown sediment until it ran clear. I also used a flushing additive to clean the system when the car was back on the road.

      Since then, the engine generally runs at about 90 deg although sometimes goes to 100 deg at idle on a warm day, and on a hot day it needs the elctric fan to assist keeping cool.

      About two weeks ago when the engine got quite hot (forgot to use the fan) some coolant ran out of the overflow, and I noticed it was a dirtly brown colour again, despite having used antifreeze with corrosion protection. Since then I drained the system, and flushed until clear, and I have put in some more flushing additive. After each run I monitor the coolant colour and it has been getting darker brown.

      I think that this indicates that the engine and/or radiator had retained some old sediment which did not shift after the first flush, but due to the reapplication of additive it is now being released. Now it seems to run cooler, around 85, and I am hoping that the cooling is now improved.

      Only time will tell if the cooling system is now adequate, but it looks promising at the moment. I will have a better idea after next weekend’s run through the mountains of Wales!

      I guess if the rad has given many years of service, not all the sediment is going to shift easily, but with perseverance maybe it is possible to get back to near enough original efficiency? What’s your experience?

    • #62520

      If you’re still getting sediment and corrosion products coming out, then in a way that’s good… the blockages are getting cleared. However, it’s possible that some of that gunk is blocking a rad leak, and you might find yourself with a pinhole somewhere along the way. The tubes in the radiator core are small, and it can take a long time to get everything out – that’s why the ‘standard’ process for clearing a radiator is to remove one or both tanks and to jam rods through the core tubes until the sediment is out. This is obviously labor intensive as well as being hard on the core if it’s done without the required care.

      Early in my Tiger ownership I had the radiator rebuilt with a four-row core. It is mounted so that the stock shroud still fits, and I previously used the ‘Canadian’ six-blade fan… I’m going to try and only use an electric fan this time around and see what happens. The four-row rad is heavy and I now think that a two-row aluminum radiator would be as efficient and about half the weight.

    • #62576

      I am glad to say that my car is now running well and showing no signs of overheating. I did have a leak appear around the coolant pump but after retightening the bolts it has now stopped.

      For me the moral is that shifting 40 years worth of crud takes more than one go, you have to persist with the flushing unitl you are sure you have cleared it all, including the block and heads.

      I recently did a 600 mile trip in the mountains and she ran just great. On one trip I was touching 125 indicated and still plently to go. Not bad for an original 260. The Tiger is surely the best car I have ever owned.

    • #62577

      chris, what kind of rpm’s were turning over in a original 260 to get upto 125? i’d be at 5400rpm at 125.

    • #62583

      Hi Chris,

      Was the ‘crud’ just the build up of grime over the years or was it material out of the block from when it was cast? Also, I assume the 125 is Mph and not Kph…quite impressive for the old girl. I don’t know if I would be that game to go that high.

      Regards, Robin.

    • #62590

      heck we do that a 1/4 mile at time, 125mph 😆

    • #62591
      quote Twin Turbo Tiger:

      heck we do that a 1/4 mile at time, 125mph 😆

      Something tells me that your engine is far from a stock little 260 small block!! 😉

    • #62592

      I did 125 MPH once with the Lister.As exhilarting as it was I’ll never go that fast again.I just like having the raw power as it is enticing to let it get out now and then.Mostly I just smile when some smart guy is trying to egg me to let some rubber off when the light turns green.It sure can bug some people because they stop and want to talk as well wanting to see just whats under the hood.The 351 does surprise them somewhat

    • #62593

      Stock 302 😕

    • #62596

      My modified 260 was timed, didn’t use radar at the time, at 147 in the early 70’s at MIS (Michigan). It was before air dams. Car was down right dangerous and unstable. Scared to death when getting out of car. Shook for an hour.

      Re, flushing. General flushing ,even with chemicals only removes the loose stuff. Therefore, if there are contaminantes, rust and compacted sedimate residing in passages etc, they will continue to be dislodged through general use. And worse, accumulactions will remain lodged in the bottom of the coolant passages affectng cooling effenciency in some cases.

      The only way to correct is to mechanically remove this crud by removing the freeze plugs and rodding the rad.

      A driveway method to flush the system after the conventional reverse flush is "boil" it. After you think your reverse flush is clean, try the boil approach. Block the rad air flow, let the car idle with a controlled boil over. That is, rig a set-up so that a small amount of pressure can build up, before it blows out, then add new water to replace expelled water. Add watter slow and at very small amounts to allow it to preheat before contacting block & heads. The mechanical agitation process of boiling water will dislodge huge chuncks of debris and gobs of sediment. Repeat several times.

      I’ve done this effectively many times with old cooling systems without any undesirable consequences. It’s messy and ugly but almost as effective as formal cleaning process during an engine rebuild.

    • #62610
      Mike Schreiner

        I run a Brass screen filter in both Tiger and my Alpine…It fits in the radiator hose and stops debri pieces…It always has sediment when I take it out to clean it….A must fo a Allum radiator…mike

      • #62613

        Re brass filter
        Now this is interesting.So far in both cars I have not had a problem regarding debris or other sedimentary stuff.Mind you I have not checked in the last little while.I have 7000 miles on the 351 but only 700
        on the 302.I’m using the best anti freeze at 50/50
        I’m wondering how you came to this conclusion and also where did you get the filter or is it just a brass screen cut to fit?

      • #62615
        Mike Schreiner

          It is a brass tube that you insert and clamp at both ends in your radiator hose…..You can unclamp one end when needed and the cone shaped screen comes out with small ss screws to clean it….or remove whole unit and backflush….I bought the Alpine one on ebay a few months ago and the tiger one I have had many years….Not sure here to get one, but if you email me I will send you a picture….It keeps the radiator fromgetting clogged up. On an allum radiator you cannot get ashop to open it and rod out the tubes…they wont do it…. email is

        • #62616

          Tried emailing .It came back.Me email address is
          Would love a picture

        • #62622

          It’s called a Gano filter

          I highly recommend. I’m running a crate engine and you’d think it would be clean. WRONG. The amount of casting material, gasket pieces and general debris is amazing. And that is a new engine. Old engines, even if supposedly cleaned have more residue. ALL engines should run Gano filters. Especially after installation.

          The Gano filter in my crate engine stays pretty clean now that the engine has about 12K miles.

        • #62624
          Mike Schreiner

            That is the one, I am using the brass one in both cars…it will pay for itself when you save the radiator from a rodding out, or if alluminum, a replacement…Mike Schreiner

          • #62626

            Thanks Tom
            It must be good if you recommend it
            I will look into getting 2 of them for sure.

          • #62641
            Mike Schreiner

              Gano filter, that is the one…the clear one looks cool, What I use is the brass one…..Mike

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