--- title: Letham: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/letham-perth-and-kinross/ location: Letham county: Perth and Kinross latitude: 56.401080 longitude: -3.467520 service: AdBlue in a Diesel Tank updated: 2026-10-21 --- # Letham: How Does AdBlue End Up in a Diesel Tank, and How Do You Avoid It? Stop reading for a moment when your diesel tank already has AdBlue in it: ignition off, engine off, and call 0333 366 0103. Around Letham, finding it before your engine turns usually leaves a drain and a thorough flush where it stands. Reading before the event? In that case what follows explains why it comes about and how to prevent it happening at all. ## AdBlue in a diesel motor, and its separate tank Diesel goes to your engine — but plenty of newer diesels driven round Letham and Woodlands hold another fluid as well. Kept in a tank of its own, AdBlue is sprayed into your exhaust stream and cleans it. There's a filler for each tank. On a lot of motors the two sit side by side under the same flap; on others the AdBlue filler is in your boot or under the bonnet. The diesel side is filled at the pump all the time. A driver who has to stop and think where it goes normally fills the AdBlue side, from a bottle, and far less regularly. It's in the gap that the error happens. ## How does AdBlue in the diesel tank take place in Letham? It is rarely carelessness. Three things tend to line up. To start with, the warning. Low AdBlue triggers a message from the vehicle, and running out leads to limp mode — so a rushed top-up, maybe before work off Tummel Road, or outside The Welcome Inn on the way home after work. Then your car is new. A hire car, a new vehicle or a company car puts the fillers where your last one didn't, and the hand hits for the cap it would have used on the old one. No part stops the tip after it has started, because a bottle with a spout goes into a diesel filler as readily as an AdBlue one. The bottle fits. The same few seconds decide it, in the middle of Letham or out in Burghmuir. ## Telling the AdBlue filler from your diesel filler Look at these first, on a forecourt in Letham or a drive out in Cherrybank. A few seconds, that's all. - The cap. The AdBlue cap is regularly blue, or marked "AdBlue". The diesel cap usually isn't. Read it rather than going by where it sits. - Check the size: the smaller neck is, on many motors, the AdBlue one. - Look inside your fuel flap: plenty of motors have a label there saying which fuel goes where. - The handbook shows which it lives if your filler is not next to your diesel cap: the boot, or under the bonnet. - The previous driver will know. Ask as you collect a hire car or fleet car — at Perth's car park, perhaps — rather than once the warning comes on. ## How to top up without AdBlue in your diesel tank Anywhere around Perth and Kinross the light comes on, here is a routine for the day. - Park then switch off. Not on a slope, not with the motor running, and not in a rush on the side of Amulree Court. - Silly as it sounds, speaking "AdBlue" out loud as you unscrew the cap works — after you have found the filler and read it. - If both sit under one flap, check the diesel cap is still closed before you lift the bottle — and leave the car on. - Pour slowly, using the bottle's own spout. Stop when it is full or when the bottle is empty. - Before starting your car, shut the cap and check a second time that the diesel cap never opened off. If at stage two or three you find you have already poured into the diesel side, stop there. Step five stays out. ## Already put AdBlue in the diesel tank around Letham? The short order of things, beginning with not starting your motor. The fuel pump starts on plenty of diesels the moment the ignition goes on — and so leave it off. AdBlue doesn't mix with diesel — it sinks to the bottom of your tank, where your fuel is sucked from — so don't top up with diesel to dilute it. If you are at a forecourt, whether it is the Tesco or the Asda, ask the staff to help push the vehicle clear of the petrol pump. Leave it where it is if you are on your own drive around Letham. Stop as soon as it is safe then switch off, if your motor has already run. On the M90, under 3 miles from Letham, that means the next junction. A short hop across Letham is a smaller job than a run towards Perth, under 3 miles away, and so tell us about how far it went. ## What happens when we arrive around Letham Outside the local primary school, near Letham St Marks or on your own drive: wherever your car has stopped, our technicians come to it. The answers settle the work and our price, so our engineers ask what went in, roughly how much, and whether it has run. You get that quote on the phone, before anyone heads out. Then the tank is cleared and the fuel system rinsed thoroughly. With AdBlue that counts more than with petrol: it crystallises and is corrosive to some of the metals in a fuel system, so it does not wash out on its own. The filter flushed or, where needed, swapped; fresh diesel in; then a check of your car. We do not leave until it has been started and is running smoothly. With pumps safe on a working forecourt and quiet enough to use outside a house at night, most jobs in which your motor has not run need about half an hour once our engineers are there. Nothing in advance; you settle up that day. At the end, a VAT invoice and a report from the engineer go to you for the insurer. Misfuelling cover is part of many insurance policies — so use the wait to check yours. ## About Letham itself Letham is a suburban area located near Perth in Perth and Kinross, sitting at an elevation of 42 metres in the inland setting of the Scottish countryside. Letham is close to several nearby places, including Burghmuir, Hillyland, and Tulloch, and is situated approximately 1.2 miles from Perth. Letham has a population of around 7540 people, predominantly residing in flat-type housing. ## AdBlue drains across Perth and Kinross, Letham included Letham is a residential suburb, and our vans that cover it also work the places around it, Hillyland and Tulloch among them, across the PH postcode area. Fastest of all: quote a PH1 2 postcode for the van. The car remains put. We drain it where it is — a side street close to Rannoch Day Centre, a lay-by on the way to Seven Acres, a driveway. If you're near a boundary, or somewhere hard to describe like the back of Letham Centre, ring and ask instead of guessing. ## In short, for Letham motorists First, the cap; then, the tip. AdBlue in your diesel tank regardless? Keep the vehicle switched off then ring 0333 366 0103; Petrol in Diesel drains it on the spot, throughout Perth and Kinross.