Banjo

Hi Francisco, I'm finding it hard, to think of anything else related to the radiator change, that could cause all these issues, if the use of the new Pimera radiator cap, does not change or solve anything. As you have advised, this problem has been there, right from the first start, after the engine rebuild, I'm left with no other answer than it is something in the engine. The only way you can completely prove this to yourself, is to fit back the original K series radiator, as you suggested. If it still happens, then it is the engine. I seem to remember a post where you were considering porting the head slightly. Is there any possibility, that you have taken too much out, & you've got a crack or tiny opening, into the water jacket it the head ? Something like that, could certainly cause a problem, similar to what you have described. Cheers Banjo

Hmmm ! Not looking good. When you "rebuilt your 5K" did you . . . . Skim the top of the block ? Skim the head ? Repair any corrosion around any of the water jacket transfer holes in the head ? Use a new head gasket with built in sealant bead around the water jacket transfer holes ? Ensure you fitted the very heavy/thick washers back under each head bolt ? The LittleRedSpirit man's suggestions are now your best suggestion, of getting to the source of this problem, now that we have ruled out the other more common, easily fixed ones. Let us know what you find. Cheers Banjo

Hi Scott, Can't really say, as mine is not in a closed situation, as you can see from the pics. Has got rid of that "tinny" sound you get from a bare exhaust pipe, so probably changes it's vibration frequency a bit. I put it on to basically stop me burning my leg, when walking around the test engine, & not concentrating, because I was intent on something else. Cheers Banjo

Hi Viterbo, Just looking at your pic of the Pimera radiator. I'm presuming that your line to your overflow/expansion bottle, is connected to the spout circled on the RHS of the above picture. Is that round bit directly below where the radiator cap fits on, a "bleeding" point for the coolant ? Looks to have a hex socket in the plastic, so could be screwed out. Is the point where the spout comes out of the Pimera radiator the same distance below the top, as the spout on the K Series radiator ? If the new Pimera radiator cap, does not solve the problem, then the question arises, why is the system not pressurising, when you unlock the radiator cap after running, & there is no pressure exhaust obvious ? That can only mean that the coolant system is not sealed elsewhere, & is not allowing the system to pressurise. Have you hooked up a cabin heater or anything other coolant line elsewhere ? There aught to be a leak displaying somewhere. If no, then the only other explanation can be an internal leak, within the engine itself., which is serious. Check oil level & discolouration etc. I do hope the new Pimera radiator cap solves the issue, because if not, I would not run the engine, until you solve the issue, for fear of damaging the engines internals. Cheers Banjo

Think we might be close to solving this. There are lots of different radiator caps, & it's "pulling a long bow", to expect an early K Series radiator cap, would work perfectly with a later model Nissan Pimera. Let us know what the results are. Cheers Banjo

I just noted this comment of yours . . . . Is the radiator cap you are using, the one that came with the Pimera radiator, or are you referring to the one from your original K Series radiator ? I'm starting to suspect, that your coolant system, is simply not pressurizing. After the engine has been running for a while, but before the overflow starts, have you removed the radiator cap, by hand, & noticed that there is a "pressure release" ? Cheers Banjo

As you have been very careful filling the engine with coolant, we can assume there are no air locks inside the block or head. Is this overflow of coolant, you are experiencing, happening when you are driving the car, or when stationary ? What is the ambient temperature where you are located ? I suggest that you disconnect the thermo-fan, so it can't switch on. Remove the radiator cap, start the car, & let it run, in a stationary position, to allow the coolant to heat up. Look down the radiator filler neck, & the coolant should be very still, until the coolant reaches the point where the thermostat, cracks open, at around 85-87 deg C. When this point is reached, little bubbles start to appear at the filler neck, & then the water starts to move & flow, as the thermostat opens further. "Not sure what you mean by " But that means the radiator is not full." The radiator should always be full in a totally closed pressurised system. As the coolant heats up & expands it increases in volume & pressure. That extra volume increases the pressure in the coolant system, & the radiator cap opens, & allows the excess coolant into the "expansion" tank. The coolant system & radiator still will be full of water. When the engine cools down, the reverse happens, & the vacuum created within the coolant system, opens the second return valve in the radiator cap, & the coolant in the expansion tank, is sucked/drawn, back into the coolant system. Most coolant overflow/expansion tanks have a mark on them showing max. This is usually about 2/3 or 3/4 of the capacity of the tank. This is when the coolant is cold. Therefore the free capacity of the expansion tank, is the volume provided for expansion overflow of the coolant. It does not require a great volume. It is important, if you are using the K Series overflow bottle, that the tube on the bottom of the cap, is not missing. Unless the overflow line is below the level of coolant in the expansion tank, it cannot draw the coolant back into the engine. That's why a lot of coolant / expansion tanks, have the overflow line connected at the bottom of the tank, so that it is always covered by coolant. Cheers Banjo

Can you explain to me why the Nissan Primera has two caps, (one for the radiator, & one for the expansion tank), & why the expansion tank cap would open at a higher pressure than the radiator ? As the overflow, from the radiator, usually only goes to the expansion, or overflow tank, I can't see why it would need a a second cap, & why it would be at a higher pressure rating. As you are using the original K Series overflow bottle, which does not have a pressure cap, I can't see that being an issue, unless your existing radiator cap is faulty. Cheers Banjo

Hi Viterbo, The blocked coolant holes at the front of the head gasket, are certainly designed to direct more flow to the rear of head, which has always run hotter than the front. I fixed this K Series issue up, but putting in an extra return path to the underside of the thermostat, from the rear of the head. I would definitely check the radiator cap, & maybe take out the thermostat, & test it's opening in some hot water on the stove; carefully noting the temp, at which it cracks open. I couldn't see from your pictures, whether you are using the original mechanical fan, or whether you have a thermofan. With a radiator that large, the coolant temp should be kept in range by just the "ram" effect of the air passing through it, whilst driving. My thermo-fan rarely comes on, as I have an LED on the dash, that illuminates, when the fan comes on, if the temp, goes above 95 deg C. Cheers Banjo

Hi Viterbo, Interesting issue, to which there must be a simple solution, but I can't quite put my finger on it as yet. I did a similar modification, but I didn't use the Nissan radiator, as although it had the inlet & outlets in the right places, it was too big. I used a Toyota Echo aluminium radiator, & the results were exceedingly good. The Echo radiator, is very close to the original size of the K series radiator. The aluminium radiators are so more efficient than the old brass ones, that my thermo-fan rarely comes on. Usually, 4-5 minutes after I have stopped, & turned the engine off, after a "spirited" run. I can imagine your engine maybe over cooling, if there was no thermostat fitted, but not overheating. Have you taken any measurements of coolant temperature around the engine ? Did the head gasket coolant holes line up OK, so the flow between block & head, was not impeded ? Does this standard expansion bottle overflow water feel really hot ? Have you simple tried a bigger vessel, in place of the existing plastic bottle ? On the Echo radiator, I used, the overflow/expansion bottle, which is part of the radiator shroud. It was much smaller than the original K series, so I was initially concerned is might be too small. It was not an issue at all. I look forward to your answers to my queries, so you can get to the bottom of this. Pretty sure the answer is going to be simple. Cheers Banjo.

Hi Simon, Welcome aboard ! First let us know where you are located. Back in the 70s & 80s, some Corollas were not imported complete. Some were manufactured in the local country, from parts, & often painted locally. Therefore if paints were sourced locally, the colours could be slightly different from country to country. That was the case here in Australia, where Rollas were assembled at AMI in Melbourne, & used local paints. Post us a picture of your car. If you believe it has never been repainted, & we know it's origin country, someone on here may well be able to assist you. P.S. A good "paint shop", should always be able to match your existing paint colour. Have a look at this website, which lists many of the Toyota paint codes. https://www.uniquecarsandparts.com.au/colour_codes_toyota_A-G.php Cheers Banjo

Hi Graeme, I've had one of those for a while now. Gets rotated around my cars. The useful thing about mine, it can alarm you, if you hit a speed limit (like 80 klm/hr) so you don't get caught driving around the city, where speed limits are constantly changing. There is a strip of road near my place that changes 5 times in about 1 kilometre. Does yours alarm ? Cheers Banjo

The mind boggles as how the exhaust & headers are going to look like, with the turbo mounted way up there high at the front ? Good luck, & keep it posted on here. Love people who are passionate, (or bored), & take on ambitious projects, that present challenging engineering exercises. P.S. Maybe it is just sitting there to tell us, it is going to have a turbo. Cheers Banjo

My wife's 2009 Corolla, gets regular wheel & tyre service at Bob Janes, where they keep tabs on it, & have full computer records of everything they have done on the car, & odometer readings at each service. My wife's car, like all our Toyotas, are fitted with Pirelli Cinturato tyres. On her last set of new tyres, fitted about 6-7 months ago, they informed me, that my wife, is the second highest listed driver on that branches records, for mileage out of a set of tyres. She achieved 94000 klms. She was pipped by another lady at Jimboomba, who only drives Jimboomba to Browns Plains return each day, & achieved 96000 klms. Cheers Banjo

I got some Loctite Super Glue for plastic today, so will have a go at fixing the broken radio surround on my BMW over the weekend. I'll let you know how it goes. Cheers Banjo